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NAME. 


No... 


DAIRY HUSBANDRY 


LABORATORY MANUAL FOR ELEMENTARY 
DAIRY HUSBANDRY COURSES 


2nd Edition 
Revised 



L. C. THOMSEN 





















DAIRY HUSBANDRY 


LABORATORY MANUAL FOR ELEMENTARY 
DAIRY HUSBANDRY COURSES 

BY 

L. C. THOMSEN 
DAIRY DEPARTMENT 
UNIVERSITY OF WISCONSIN 


2d Edition, revised 
COPYRIGHTED 
1923-1924 
L. C. THOMSEN 
































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©C1A807S59 


NOV 17 1924 

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INTRODUCTION 

The exercises listed in this manual are designed for introductory courses 
in Dairy Manufacturing. A sufficient number of exercises is included to 
cover eight semester hours (four-fifths) of laboratory work. It is, however, 
best adapted to a course of four or six semester hours (two or three-fifths) 
of laboratory work, since it will then permit a wide choice of exercises, 
according to the type and ability of the student. In case of the tright or 
fast working student additional exercises may be assigned. A number of 
so-called elementary exercises have been omitted from this manual, be¬ 
cause their inclusion would be impractical. In some instances this was 
done because the apparatus and material necessary would be too expensive, 
in others it was merely a matter of choosing the simpler and shorter 
method. 

It is not the purpose to have this manual serve as a text book, but it 
should act as a guide or aid in the study of the text. The manual suggests 
the plan of the work, but for detailed instructions on the operation, the 
text should be used. At the foot of most exercises are given specific 
references to text books most commonly used for a course of this kind. 
Supplementary references to books pertaining to da'rying, found in agri¬ 
cultural libraries, are also included where they seem particularly pertinent. 

The manual is divided into two parts, each of which in turn is divided 
into series of exercises. Part I deals with the analysis of dairy products. 
Part II takes up the home manufacture of several common dairy products. 
Any or all of the exercises of a series may be given for class work. 

Preceding Series I part I is given a list of material that may be checked 
out to each student at the opening of the course or at intervals throughout 
the course as needed. The list is sufficient for a class of ten students. 
Preceding every other series is given a list of additional material necessary. 
A * precedes those items used for but one exercise in the series. 

Attendance: Each student is expected to attend regularly at the open¬ 
ing of the laboratory period and to remain in attendance until the close 
of the period. If his experiment has been completed long before the period 
ends, he should report to the instructor for additional work. An excellent 
plan from the viewpoint of both student and instructor is the initialling 
by the instructor of the observations recorded in the manual by the stu¬ 
dent. This serves as a check on the laboratory attendance, and also in¬ 
forms the student that the exercise is ready for final transcription. The in¬ 
structor will meet the class as a whole in one of the lecture rooms im¬ 
mediately preceding the laboratory period. At this time he will give any 
additional instructions or assignments that he deems necessary. 

Absences must be made up by arrangement with the instructor within a 
reasonable time of their occurrence, usually two weeks. In cases of illness, 
for which a medical excuse has been presented, this time may be extended. 

While in the laboratory the student should conduct himself as a dairy¬ 
man and student. The prime requisite of a dairyman is cleanliness, and 
a student is not expected to leave the laboratory until it is in satisfactory 
condition. 


2 


LABORATORY MANUAL 


Lecture Notes: Lecture notes should be written up in such manner 
that the note book is presentable at any time it may be called for. Each 
day’s lecture should be begun on a new page, and should bear a date. 
The above does not refer to instructions given preceding the laboratory 
period. If the instructor so desires he may call for the manual and labora¬ 
tory notes at any time. 

Reports: The regular reports should be made on 8x11 paper and handed 
in at the period following the performance of the experiment, unless other 
arrangements are made by the instructor. The reports should be written 
with ink or typewritten and should be in the form outlined below: 

1. Number of experiment; name and number of student. 

2. Object: As given in the manual. 

3. Procedure: Apparatus used; a brief description. 

4. Observation: Filled in and copied in exercise as outlined in the 
manual. 

5. Questions: The question should be copied, and it should be followed 
by a comprehensive, but concise answer. Additional questions may be 
given by the instructor. 

A two-inch margin should be left on the left hand side of the page for 
notations by the instructor. Corrections should be made as requested and 
the exercise should again be handed in for credit. 

Materials supplied by the student: 

(1) Text book 

(2) Laboratory Manual 

(3) An acid-proof apron or a pair of overalls 

(4) Dividers 

(5) Grease pencil to write on glass 

(6) Note book, loose leaf, 8x11 

L. C. THOMSEN. 

Abbreviations: 

F. & W.—Farrington and Woll—Testing milk and its products (1924). 

Van S.—L. L. Van Slyke—Modern methods of testing milk and milk 
products (1912). 

St.—W. A. Stocking—Manual of milk products (1917). 

Jud.—H. F. Judkins—Principals of dairying (1924). 


Introduction to second revised edition 

Since the publication of the first edition of this Manual, it has been 
found advisable to make a number of minor changes so that the exercises 
might be of a greater general interest. It has also been deemed advisable 
to drop several little used exercises and replace them with exercises per¬ 
taining to more recently developed dairy tests. It was also thought 
advisable to enlarge the appendix by the addition- of a number of tables 
of general interest to the student of dairying.—L. C. T. 



CONTENTS 


PART I. ANALYSIS 

Page 

Introduction. 1 

Series A. Preliminary Exercises. 5 

1. Cleaning laboratory equipment. 6 

2. Determining the accuracy of glassware. 7 

3. Determining speed of centrifuges. 8 

4. Determining strength of sulfuric acid. 9 

5. Etching glassware. 10 

Series B. Testing milk for fat. 11 

6. The Babcock test. 11 

7. Effect of weak acid. 13 

8. Effect of temperature. 14 

9. Testing partially churned milk. 15 

10. Testing Soured milk. 17 

11. Rapidity with which fat rises on milk. 19 

12. Effect of speed. 20 

13. Effect of temperature o' reading. 21 

14. Testing composite samples. 22 

15. Standardi ing milk and cream. 23 

16. The Sin-acid test. 25 

17. The.Rose-Gottlieb test. 27 

18. Effect of souring on fat content.. 28 

19. Fat content at various stages of milking. 28 

20. Variations of fat content of the milk of one cow. 28 

Series C. Cream testing. 29 

21. Testing Cream for fat. 29 

22. T< sting cream by volume. 30 

23. Testing cream using various weights.... 31 

24. Several methods of testing cream. 32 

Series D. Testing buttermilk, skimmilk, and whey. 33 

25. Testing Skimmilk. 33 

26. Testing Buttermilk. 34 

27. Testing whey. 36 

Series E. Lactometer.. 37 

28. Testing accuracy of lactometer. 37 

29. Use of Quevene Lactometer. 38 

30. Adulteration formulae. 39 

31. Adulteration of an unknown sample of milk. 41 

Series F. Acidity testing. 43 

32. Preparation of alkaline solutions. 43 

33. Mann’s test for acidity. 45 

34. Farrington Alkaline Tablet test. 47 

35. Farrington Rapid Method test. 48 

Series G. Casein testing. 49 

36. Hart Casein test. 49 














































1 


LABORATORY MANUAL 


P.ige 

37. Walkers casein test. 51 

38. Van Slyke’s casein test. 52 

Series H. Butter testing. 53 

39. Farrington test for fat in butter. 53 

40. Factory moisture test. 55 

41. Salt test. 56 

42. Ether extraction test for fat in butter. 57 

Series I. Cheese testing. 58 

43. Fat test. 58 

44. Moisture test. 60 

Series J. Ice cream testing. 61 

45. Sulfuric acid fat test. 61 

46. Glacial Acetic and Hydrochloric fat test. 62 

47. Acetic and sulfuric fat test.. 63 

48. Benkendorf overrun test. 64 

Series K. Condensed milk testing. 65 

49. Fat content of unsweetened condensed milk. 65 

50. Specific gravity of condensed milk. 66 

Series L. Special quality tests. 67 

51. Wisconsin sediment test. 67 

52. Methylene blue reduction and fermentation tests. 68 

53. Alcohol test. 70 

54. MarschalJ Rennet test. 71 

PART II. MANUFACTURING 

Series A. Butter... 72 

1. Manufacturing dairy butter. 72 

2 . Effect of temperature. 74 

3. Effect of acidity. 75 

Series B. Cheese. 76 

4. Cottage cheese. 76 

5. American cheese. 7 g 

Series C. Ice Cream. go 

6 . Ice cream. go 

Series D. Hand separators. g 2 

7. Construction. g 2 

8 . Capacity and efficiency of separators. 84 

9. Effect of temperature on skimming. g 6 

10 . Effect of speed on skimming. 87 

11. Effect of richness of milk on skimming. 88 

12 . Effect of rate of inflow on skimming. 89 

Appendix... 90 










































PART ONE—ANALYSIS 


SERIES A. 

I 

Cleaning glassware, determining the accuracy of glassware, 
proper speed of tester, strength of acid. 

Materials: Since these are in fact preliminary exercises, the material 
required is the same as is necessary for the ordinary Babcock 
milk testing process. The unstarred items of the list given 
may therefore act as a guide for material to be checked out to 
each student. 

(.Material for 10 students )— 

40 — 10% Babcock milk test bottles. 

20—30 % 6", 9 or 18 gr. Babcock cream test bottles. 

10 — 17.6 cc. pipettes. 

10 — 17.5 cc. acid cylinders. 

10—1 pint fruit jars or 1 pint milk bottles. 

10—1 quart enameled cup$. 

10—Test bottle brushes. 

10—25 cc. or 50 cc. Burettes. 

10 — 8.8 cc. pipettes. 
lO—'A pt■ white cups. 

10—Aluminum Beakers ( 125cc .). 

10—100 cc. cylinders. 

10—Lactometer cylinders. 

10—Quevene Lactometers. 

5—gallons Sulfuric acid. 

5—Balances (Torsion moisture type). 

2—Enclosed Babcock testers (power or hand). 

10—Pounds washing powder. 

5—Thermometers ( Pasteurizing). 

5—9 gr. weights. 

5—18 gr. weights. 

5—10 gr. weights. 

*10—10% Trowbridge calibrators. 

*10 — 30% Trowbridge calibrators. 

*2—Speed indicators. 

* 2—Quarts cleaning solution (4 oz. potassium di-chromate crys¬ 

tals and 2 quarts H 2 SOf). 

* 2—Acid hydrometers. 

* 2—Westphal balances. 

*80—Strips blotting paper (}4"x5"). 

* 1—Pound paraffin. 

* Yl—P int etching solution (67 gr. of 48% Hydrofluoric acid and 

28 gr. of C P Ammonium Fluoride) to be kept in a wax, para¬ 
ffined or rubberized container. 

* 1—Lead dish (100 cc.). 

* 1—Cover glass. 

*1 — File. 

*50 gr.—Calciupi Flouride (Ca FU). 


I ABOPATORY MANUAL 


() 

EXERCISE NO. 1. 

Object: To properly clean laboratory equipment. 

Procedure: One of the most important, yet often neglected parts of the 
laboratory work of a dairy manufacturing plant,is the cleaning 
of glassware. Dirty glassware not only indicates slovenliness, 
but it is also conducive to inaccuracies in the work. If the glass¬ 
ware is properly cleaned immediately after use, it is very easy 
to keep clean. 

A. Bottles containing acid or milk should be shaken well when 
emptied so as to remove sediment and then rinsed out in clean, 
warm water, and filled with soap suds by submerging. With 
bottles about two-thirds full of soap suds, shake vigorously. 
Empty the bottles of the soap solution and rinse in clear warm 
water. Place aside to drain. Ordinarily the above procedure 
will maintain the glassware in a clean condition. 

B. If the treatment under A does not remove the scale on the 
inside of the bottle, pour into the bottle about 5 cubic centi¬ 
meters of the prepared cleaning solution and be sure it comes 
in contact with the scaled surfaces. Set the bottle aside for 
several minutes, and shake occasionally. Drain this solution 
from the bottles and proceed as under A above. 

Note: The cleanliness of Babcok glassware may be checked 
by running a blank test with clean water and suFuric acid, 
using the same proportions as in the milk test (See exercise 6). 

Observations: 

Conclusions: 

Questions: (1) If no cleaning solution is available what other methods 
can be suggested for removing scale from the inside of the bot¬ 
tle? 

(2) Enumerate several conveniences for use in washing glassware. 

(3) What is the average specific gravity of cow’s milk? 

(4) What is the weight of a charge of milk delivered by a 17.6 cc. 
pipette? Show by use of figures. 

References: F. & W. f 46, 47, 48; Van S. pp. 53-55, 175-176; Jud. 70-71. 


1 AIRY HUSBANDRY 


EXERCISE NO. 2 

Object: To determine the accuracy of the glassware used for making the 
Babcock lest. 

Procedure: Some state laws specify that only tested glassware is to be 
used for making the Babcock test. There are several methods 
used for determining the accuracy of the glassware. Each 
test bottle should be tested by at least two of the methods sug¬ 
gested. 

A. Calibrate each of the 10% milk test bottles with the proper 
Trowbridge calibrator, and do likewise with the 30% cream 
test bottles. Record results for the half, and for the whole 
scale. Particular care should be taken to have the neck of the 
bottles dry. Blotting paper is provided. Avoid air bubbles. 

B. Determine the accuracy of each bottle at the half and the 
whole scale by using an accurately graduated burette. Observe 
the same precautions as for A. 

C. Determine the accuracy of the whole scale by balancing the 
bottle when filled to the : ero mark with distilled water, and 
weighing again when filled to the highest graduation. 

D. Measure the length of the scale of each of the bottles and 
record as milimeters. 

E. The pipette may be calibrated by weighing a small, clean, dry 
beaker and emptying the pipette which has been filled to the 
17.6 cc. mark with distilled water at 20° C. (68° F.) into the 
beaker. The last few drops may be expelled from the pipette 
by closing the top with a finger, while the bulb is being warmed 
with the hand. Weigh the beaker with the water. The pipette 
should deliver 17.6 grams of water. 

F. Another method for determining the accuracy of the pipette is 
to empty it when filled to the 17.6 cc. mark into a graduated 
burette which has been emptied to the 20 cc. mark. The 
pipette should deliver nearly 17.6 cc. of water. 

G. The acid cylinder, for information only, should be calibrated 
by using the burette. 

See F. & W. If 307 for complete specifications of bottles and pipettes. 

Conclusions: 

Questions: (1) Describe in detail the calibration of test bottles with 
mercury. 

(2) What is the c pacity in cc. of the neck of an 8% milk test 
bottle? A 10% bottle? A 30% cream test bottle? What is 
the weight of a volune of butter fat at 140° F. in each of the 
above bottles when it just fills the neck from 0 to the highest 
graduation? 

(3) Why is the neck of a test bottle constructed so that the vol¬ 
ume represented by one per cent is equal to .2 cc? 

(4) What are the legal requirements for Babcock glassware in 
this state? 

References: F. & W. If 44, 44a, 48, 49, 50, 53-63, inclusive. Van S. pp. 
46-53; Jud. pp. 64-66; St. pp. 105-109. 


8 


LABORATORY MANUAL 


EXERCISE NO. 3 

Object: To determine the proper speed of the Babcock centrifuges 
Procedure: Dr. Babcock, in his early work with the tester, found that with 
a diameter of 18", the optimum separation was obtained at a 
speed of 700-800 R. P. M. This gives a centrifugal force 
of approximately 30.65 pounds. (F. & W. If 66. 

A. If 800 R. P. M. is used as the correct figure for an 18-inch 
tester, then the speed of any other tester can be calculated by 
using the formula. 


R. P. M. = /-=radius of tester studied. 

V r 

B. With a speed indicator determine the steam pressure neces¬ 
sary to operate the tester when empty, when half filled, and 
when full. 

Note. In obtaining the diameter of a tester, it should be 
measured with the cups extended. 

Observations: 


Tester 

Diameter 

Speed 

lbs. pressure 
empty 

lbs. pressure 
H full 

lbs. pressure 
full 

1 






2 






3 




; 



Conclusions: 

Questions: (1) Give the table of speeds for testers having a diameter 
of from 10-24 inches, progressing by 2. 

(2) Describe a method for determining the necessary speed of 
testers when no speed indicators or formulas are available. 

(3) What advantages are claimed for a steam tester over a belt, 
water motor, or hand power tester. 

(1) Give the average composition of normal cow’s milk. 

References: F. & W. 15-22, inclusive; 64-71, inclusive: Van S. p. 
15, 38-43; Jud. 69; Si. 16-20. 






















DAIRY HUSBANDRY 


9 


EXERCISE NO. 4 

Object: To determine the strength of the sulfuric acid used for the Babcock 
test. 

Procedure: Sulfuric acid for the Babcock test should have a specific 
gravity of 1.82-1.83 or should be 90-92% pure. 

A. The specific gravity may be determined by using the Westphal 
balance as follows: The balance should be leveled carefully. 
The screw on the beam should be adjusted so that it balances 
exactly with the plunger suspended in the air. The glass 
cylinder should be filled with acid at 15° C. (59° F.) and placed 
so that the plunger will just be submerged. Proper weights 
are thus placed on the beam until it again balances. Take the 
reading. 

B. Place acid at a temperature of 15° C. (59° F.) in a tall glass 
cylinder and insert acid hydrometer. Read the specific gravity 
direct. 

Note: Great care should be taken to avoid having acid come 
in contact with metal or wood. 

Observations: 


Sample 

Temperature 

Sp. gr. 

Sp. gr. 



Westphal 

Hydrometer 

1 




2 





Conclusions: 

Questions: (1) What effect has temperature on the specific gravity of 
sulfuric acid? 

(2) What happens if a bottle of sulphuric acid remains unstop- 
per^d? 

(3) Give 3 reasons why sulfuric acid is used when making a Bab¬ 
cock test for fat in milk. 

(4) Describe another method of determining the specific gravity 
of sulphuric acid. 

References: F. & W. f 72-78, inclusive; Van S. pp. 43-46; Jud. 62; St. 
P. 115. 













10 


LABORATORY MANUAL 


EXERCISE NO. 5 

Object: To become acquainted with methods of etching and labeling glass¬ 
ware. 

Procedure: All newer glassware has a space provided on the bulb for 
writing. However, it is sometimes desired to etch numbers 
on glassware or to produce roughened surfaces for writing. 
This may be done as follows: 

The student should familiarize himself with at least two 
methods. 

A. Take a piece of paper of the desired shape and stick it on the 
bottle over the spot to be etched. Immerse the bottle in hot 
paraffin. Remove the paper by cutting the paraffin around it. 
Place etching solution on the exposed surface for 20 seconds to 
1 minute. Wash off the solution and try to write on the sur¬ 
face. If unsatisfactory, repeat the treatment. A number may 
be etched on the bottle by merely scratching the number 
through the paraffin. 

B. Prepare surface to be etched as indicated under “A” above. 
Place some calc um Flouride in a lead dish. Add enough 
sulfuric acid to form a paste. Allow the fumes to come in con¬ 
tact with the exposed glass surface, or spread a small quantity 
of the paste over the exposed surfaces. 

Note: Whenever hydroflouric acid is produced, the process 
should be carried on under a hood or at an open window. 

C. A rough surface may be produced on glass by using a fine steel 
file, dipped in water, and passed over the surface to be rough¬ 
ened, several times. 

D. There are two commonly used methods for protecting labels 
on reagent bottles: 

(1) Use a good mucilaged label and on it write the desired 
information with India ink. Place the label on a pre¬ 
viously cleaned surface of the bottle, and when dry, 
paint the labeled part entirely with very hot paraffin, 
or dip the labelled part in paraffin. 

(2) Proceed as under “1” above, but cover the labelled area 
with shellac. 

Observation: Record time required for the solution to act. 

Conclusion: 

Questions: (1) Give a definition for legal milk in this state. 

(2) Of what is the ash of milk composed? 

(3) What is meant by the term vitamines, and state briefly how 
milk compares with other foods in vitamine content. 

(4) What is colostrum milk? How does it differ from normal milk? 

References: F. & W. U 20, 23; Van S. pp. 1-19; Jud. pp. 22-28; St. 
pp. 28-29; 37-38. 


DAIRY HUSBANDRY 


11 


SERIES B 

Testing Milk for Fat 

Materials necessary for 10 students: 

* 1—Pint Sin-acid solution. 

* 4—Ounces caustic soda or caustic potash , or washing powder. 

* A—Gallon Ethgl ether. 

* A—Gallon Petroleum ether. 

* 1—Pint 95% Elh ■ alcohol. 

* 1—Pint aqua ammonia. 

* A—gallon distilled water. 

* 10— Rohrig extraction tubes ( Rose-Gottlieb test). 

* 1 — Hood. 

* 1—Hot plate. 

1—Hot water bath. 

* 1—Sensitive balance. 

EXERCISE NO. 6 

Object: To become acquainted with the operation of the Babcock test. 

Procedure: A demonstration of the important steps in the test will be 
given by the instructor, preceding the laboratory period. In 
order that the main points may be fixed in mind, they are given 
below in the order of perform rce. 

A. (1) Procure a representative sample of milk (about 100 cc.) and 
mix thoroughly by pouring back and forth from one container 
to another at least six or more times, depending of course, on 
the condition of the sample. 

(2) Immediately after mixing, transfer 17.6 cc. of the sample to a 
10% milk test bottle. Blow the last few drops from the 
pipette. 

(3) Measure out 17.5 cc. of acid and pour into the bottle so that 
it runs down the side of the neck and rinses off adhering milk. 

(4) Mix the milk and acid thoroughly by giving the bottle a ro¬ 
tary motion. Mixing cannot be overdone. 

(5) Whirl the bottles in the centrifuge for five minutes at a speed 
which will produce 30.65 pounds pressure per square inch on 
the bottom of the bottle. Bottles should be placed so that the 
tester is balanced. (See Ex. 3, Series A.) 

(6) Add hot water (at least 140° F.) up to the neck of the bottle 
and whirl two minutes. 

(7) Add enough hot w ater (at least 140° F.) to bring the fat column 
between the 0 and 10% marks, and whirl one more minute. 

(8) If-a steam turbine tester is used, remove bottles from tester 
and with a pair of dividers read the entire fat column (including 
the low T er and upper menisci). If the temperature of the fat 
column is not within the 120°-140° F. limits, a hot water bath 
deep enough to permit the fat column to be submerged, should 
be used for four minutes. If dividers are not at hand, the per 


12 


LABORATORY MANUAL 


cent of fat may be obtained by subtracting the reading ob¬ 
tained at the base of the fat column from the reading obtained 
at the top of fat column. 

Note: (1) Since sulfuric acid is very corrosive, great care 
should be exercised when handling it. 

(2) Acid bottles should be kept stoppered when not in use. 

(3) The enclosed type of testers are preferable and they should 
be kept closed when operated. 

Observations: Record results as follows: 


Sample 

% fat 

Color of 
fat 

Condition 
of fat 

Condition of 
acid mixture 

1 





2 





3 






Conclusion: 


Questions: (1) Describe how a sample of frozen milk should be obtained 
for the Babcock test. 

(2) Why are bottles filled twice with hot water and whirled three 
times rather than filling once and whirling once? 

(3) When should a water bath at 120°-140° F. be used when test¬ 
ing? Why? 

(4) Why is the acid poured in such a manner that it runs down the 
side of the bottle under the milk, and not directly into the 
milk? 


References: F. & W 7 . If 29-42, inclusive, 66; Van S. p 23, 57-70; Jud. pp. 
41-75; St. pp. 112-119. 













DAIRY HUSBANDRY 


13 


EXERCISE NO. 7 

Object: To study the effect of weak acid on results obtained by the Babcock 
test. 

Procedure: “It is indeed remarkable what slight difference in the specific 
gravity of the acid will make themselves apparent in the work¬ 
ing of the test.” (F. & W. f 75.) 

A. Make each of the following tests in duplicate: 

(1) 17.6 cc. of milk and 17.5 cc. of acid (sp. gr. 1.82-1.83). 

(2) 17.6 cc: of milk and 17.5 cc. of weak acid (sp. gr. 1.78) 1 
part water to 20 parts acid. 

(3) 17.6 cc. of milk and 21-23 cc. of weak acid of test No. 2. 

(4) 17.6 cc. of milk and 17.5 cc. of weak acid heated to 100° F. 
before using. 

Note: For preparing the weak acid see F. & W. f 74. Never 
dilute sulfuric acid by pouring water into it. 

Observations: Record results and observations as follows: 


Sample 

Temperature 

% fat 

Color of fat 

Condition of fat 

Milk 

Acid 

1 

a 






b 






2 

a 






b 






3 

a 






b 






4 

a 






b 







Conclusion: 

Questions: (1) Show by using figures how a 5% reading would be influ¬ 
enced if read at 180° F. instead of at 140° F. 

(2) What precaution should be taken if sulfuric acid is too strong? 

(3) Give 5 reasons why the fat column may be dark in color or con¬ 
tain black spots, or have dark curd directly underneath? 

(4) Give 4 reasons why the fat column may be light in color, or 
contain light spots, or have light curd directly beneath? 

References: F. & W. f 72-79, inclusive; Van S. pp. 43-46; 65-70; Jud. 71; 
St. pp. 118-119. 























14 


LABORATORY MANUAL 


EXERCISE NO. 8 

Object: To determine the effect of temperature of the milk and the acid on the 
color and condition of the fat column. 

Procedure: The ideal fat column should be a clear golden or amber color 
with a decided sparkle and should freely transmit light rays 
in an unbroken course within the column. A fat column lack¬ 
ing in any of the above indicates an imperfect test. There is 
no question that curd within or beneath the fat column affects 
the reliability of the results. 

A. Use 17.6 cc. of milk in each and make each of the following tests 
in duplicate: 

(1) 17.5 cc. of acid at normal temperatures (65°-75° F.) 

(2) 17.5 cc. of acid at a low temperature. (Below 55° F.) 

(3) 20-21 cc. of acid at a low temperature (Below 55° F.) 

(4) 17.5 cc. of acid at a high temperature. (98°-105°F.) 

Observations: 


Sample 

i • 

Tempe 

irature 

C. C. of 
Acid 

% fat 

Color 

Condition 

Milk 

Acid 

1 

a 







b 

a 







2 







b 







3 

a 







b 







4 

a 







b 








Conclusion: 

Questions: (1) Why should the fat column of a milk test be read so as 
to include both menisci? 

(2) What effect on the test will the practice of allowing the acid 
and milk mixture to stand for a few minutes before centrifug¬ 
ing have? 24 hours? 

(3) What may cause foam on top of the fat column? How may 
this defect be remedied? 

(4) Give the important developments which resulte4 from the in¬ 
vention of the Babcock test. 

References: F. & W. If 79, 80, 307 (Table 2), 39, 41; Van S. pp. 64-70; 
Jud. pp. 66-72; St. pp. 118-119. 


























DAIRY HUSBANDRY 


15 


EXERCISE NO. 9 

Object: To make an accurate test of partially churned milk. 

Procedure: A fat test of partially churned milk is one of the most difficult 
tasks of testing, for exceptional care must be taken to obtain 
reliable results. 

A. Obtain about 500 cc. (1 pint) of milk, having a temperature be¬ 
low 60° F. Measure out duplicate samples. Divide the re¬ 
maining milk into three approximately equal parts. Redivide 
one of the tree lots in two equal parts and set aside in the 
locker for future use. Then proceed as follows: 

(1) Cap one of the two remaining containers securely and shake 
with a churning motion until large butter granules form. 
Do not mistake foam for butter. 

(a) Melt the fat in the churned sample by placing the con¬ 
tainer in warm water (110° F.) until all of the granules 
have liquified. 

(b) Shake the mixture vigorously until completely mixed. 

(c) Sample at once for testing. 

Note: This step requires very great care and rapidity 
of operation, since liquid fat in the form of large fat glob¬ 
ules separates very rapidly from the serum. 

(2) Cap the second container securely and churn the sample as 
above. 

(a) Add a known quantity of ethyl ether (10-20 cc. will 
usually suffice) to dissolve the butter granules. 

(b) After the granules have been completely dissolved, mix 
thoroughly and test in duplicate. Calculate the per 
cent fat according to F. & W. If 31. 

Note: Care should be exercised in adding acid to warm 
milk or to milk containing ether. A few cc.’s should 
be added at a time and the bottle well shaken after each 
addition, as otherwise the action may be very violent. 


16 


LABORATORY MANUAL 


Observations: 


Sample 

Treatment 

% fat 

Color 

Condition 

1 

a 

Normal 




b 

“ 




2 

a 

Heated to 110° 




b 

“ 




3 

a 

cc. ether added 




b 

“ 





Conclusions: 

Questions: (1) Give the composition of milk of the four principal breeds 
of cattle. 

(2) Name the leading breeds of cattle which produce milk with rela¬ 
tively small fat globules; with relatively large fat globules. 

(3) What special precautions should be observed when using a 
hand tester in a cold room? How may these difficulties be over¬ 
come? 

(4) How may churning of small samples of milk in transit be 
avoided? 


References: F. & W. ^ 30, 31; Van S. pp. 1-23; Jud. p. 30, 45; St. pp. 
41-45, 132. 


















DAIRY HUSBANDRY 


17 


EXERCISE NO. 10 

Object: To test thick soured milk for fat. 

Procedure: “When milk becomes sour, the casein is coagulated and the 
mechanical condition of the milk thereby changed so as to 
render difficult a correct sampling.” (F. & W. f 32.) 

A. The two samples of milk held over from Exercise 9 to sour and 
thicken, are liquified by the following two methods: 

(1) To one of the samples add a small quantity O^-T gram) of 
some solid alkali (sodium hydroxide or potassium hydrox¬ 
ide). Shake from time to time, and when completely 
liquified obtain duplicate samples for testing. 

Note: Do not try to hasten the process by a too rapid ad¬ 
dition of the alkali. 

(2) To the second sample add a definite quantity (2-5 cc. may 
be sufficient) of strong aqua ammonia in quantities of 1 cc., 
and shake well after each addition. When the sample has 
been completely liquified, obtain duplicate samples for 
testing. Calculate the correct test as for partially churned 
milk. 

Note: (1) Extreme care should be exercised when adding 
acid to an alkaline solution. Avoid accidents by adding 
the acid in small quantities. 

(2) A soda washing powder, e. g., Wyandotte may be sub¬ 
stituted for either of the above alkalies. 

Observations: 


Sample 

cc. of 
milk 

Alkali 

used 

Amount 
of alkali 

Reading 

% fat 

1 

a 






b 






2 

a 

, 





b 






3 

a 






b 

i 







Conclusion: 




















18 


LABORATORY MANUAL 


Question: (1) If 8 cc. of ammonia are added to 200 cc. of sour milk and 
the reading obtained is 3.7, what is the correct test of the milk? 

(2) If a sample of milk obtained from a 3568 pound lot gives a test 
of 3.6%, how many pounds of butter fat does the milk contain? 

(3) The following lots of milk are delivered by a patron during the 
week: 

Monday, 952 pounds testing 3.4%. 

Tuesday, 625 pounds testing 3.8%. 

Wednesday, 821 pounds testing 3.6%. 

Thursday, 690 pounds testing 3.5%. 

Friday, 582 pounds testing 3.7%. 

Saturday, 736 pounds testing 3.9% 

What was the total quantity of fat delivered by the patron 
during the week? 

(4) What is the average test of the milk delivered by the patron in 
problem 3? 

References: F. & W. H 32, 196; Van S. 23, 24; Jud. pp. 41-58; St. p. 
132. 


DAIRY HUSBANDRY 


19 


EXERCISE NO. II 

Object: To determine the rapidity with which fat rises on milk. 

Procedure: Since butterfat maintains its identity in the milk and is in 
suspension, it rises to the surface due to the fact that its spe¬ 
cific gravity is considerably less than that of the serum. The 
rapidity with which the fat rises, however, depends on other 
factors beside specific gravity. 

A. Fill three cylinders with a well mixed sample of milk previously 
tested in duplicate. 

B. Test the top layer and the bottom layer of milk in cylinder 
number 1 after it has stood 10 minutes. First remove samples 
from the top—then by closing the upper end of the pipette, 
lower it in the milk and remove a sample from the bottom of 
the cylinder. 

C. Repeat the above process with the second cylinder after 20 
minutes. 

D. Repeat the above process with the third cylinder after 30 
minutes. 

Observations: 


San 

iple 

Time Stood 

Layer 

Results 

Color 

Condition 

1 

a 






b 






2 

a 






b 



• 



3 

a 






b 






4 

a 






b 







Conclusions: 

Questions: (1) Name the fats of which butter fat is composed, and state 
how the various butter fats differ from each other. 

(2) How can true butter be distinguished from oleomargarine? 

(3) Name the factors which influence the rapidity with which fat 
rises on milk. 

(4) Describe butter fat globules with reference to size, number, 
shape etc• 

References: F. ’& W. IF 15, 17, 29; Van S. pp. 3-8; jud. pp. 25-26; St., 
pp. 20-23, 69-73. 



































20 


LABORATORY MANUAL 


EXERCISE NO. 12 

Object: To determine the effect of speed of the centrifuge on the reading of 
the fat column. 

Procedure: “It is vitally important that the required speed be always 

kept up;.if the speed is slackened, the results obtained 

are too low; it may be a few tenths, or even more than one per 
cent.” (F. & W. If 67.) 

A. Make a duplicate test of a sample of milk with the centrifuge 
operated at the prescribed rate of speed. 

B. Make a duplicate test of the same sample of milk when the 
tester is being operated at one-half the correct rate of speed. 

Note: The correct rate of speed for testers of various diam¬ 
eters is given in F. & W. H 66. 


Observations: 


Sample 

Diameter 
of tester 

Speed 

% fat 

Condition 

Color 

1 

a 






b 






2 

a 






b 







Conclusions: 


Questions: (1) Explain the distribution of the components of milk in 
buttermaking, cheese making, and ice cream making. Write 
the answer in the form of a table. 

(2) What causes souring of milk? Explain. 

(3) Discuss the condition of the casein as found in normal cow’s 
milk. 

(4) What is meant by the term viscosity of milk, and how may 
the relative viscosity be determined? 

References: F. & W. % 18, 19, 23-27 inclusive, 66, 67, 68; Van S. pp. 16, 
131-132; Jud. pp. 26-29, 102 111; St. pp. 23-37. 





















DAIRY HUSBANDRY 


21 


EXERCISE NO. 13 

Object: To determine the effect of temperature on the reading of the fat 
column. 

Procedure: “A difference of 40° F. in temperature when reading a fat 
column obtained in the case of a 10% milk, will make a differ¬ 
ence in the reading of .14%.” (F. & W. \\ 41, footnote.) 

A. Test a sample of milk in duplicate in the usual way. 

B. Remove the bottles from the tester and place in a water bath 
at 100° F. Read after 3 minutes. 

C. Place the bottles, after reading, in a water bath at 140° F. 
Read after 3 minutes. 

D. Place the bottles, after reading, in a water bath at 180° F. 
Read after 3 minutes. 

Note: Be sure to have the upper surface of the fat column 
beneath the surface of the water in the water bath. 

Observations: 


Sample 

Temperature 
of water bath 

% fat 

Color 

Condition 

1 

a 





b 





2 

a 

b 









3 

a 





b 






Conclusions: 

Questions: (1) If the graduations of a test bottle measure 2.3 cc. from 
0-10%, what would be the correct test of a sample of milk 
which reads 3.7% fat in this bottle? 

(2) Mention at least six causes of variations in the test of a cow’s 
milk. 

(3) How do changes in the feed of a cow influence the quantity and 
the quality of her milk? 

(4) How does the test of the milk yielded by a cow generally 
change with the advance of the period of lactation? 

References: F. & W. If 159-163 inclusive, 174-177 inclusive, 41 42; 
Van S. pp. 1-8, 66-67; Jud. pp. 30-59, 69-70; St. pp. 41-68. 


















22 


LABORATORY MANUAL 


EXERCISE NO. 14 

Object: To become acquainted with the proper method of obtaining and test¬ 
ing a composite sample of milk. 

Procedure: A composite sample of milk or cream is a mixture of each 
weighing of milk, taken in such a manner that it shall be pro¬ 
portional to the total weight of milk or cream tested. 

A. Test separately each of the three samples of milk provided, 
which were taken from lots of milk weighing 200, 300, and 400 
pounds respectively. Calculate the true average test of the 
samples of milk according to F. & W. f 196, 197, 198. 

B. Take an equal sample (one pipetteful) from each lot of milk, 
mix thoroughly and test in duplicate. 

C. Take a correct composite sample (2 pipettefuls from the 200 
pound lot, 3 pipettefuls from the 300 pound lot, etc.) mix 
thoroughly and test in duplicate. 


Observations: 


Sample 

% fat 

Average 

Color 

Condition 

1 

a 






b 






c 





2 

a 






b 





3 

a 






b 






Conclusion: 

Questions: (1) Give a brief description of six different appliances used 
for obtaining a composite sample of milk. 

(2) Name the preservatives commonly used for composite samples 
of milk. 

(3) Why is it not advisable to practce composite sampling and 
testing of cream in creameries? 

(4) Describe in detail how composite samples should be cared for. 

References: F. & W. If 179-199 inclusive; Van S. pp. 24-31; Jud. pp. 
46-58; St. pp. 109-112, 122. 





























DAIRY HUSBANDRY 


23 


EXERCISE NO. 15 

Object: To become acquainted with the principal of standardizing milk and 
cream. 

Procedure: The legal standard for fat in cream is 18% in the United 
States. It is permissible to reduce the test of rich cream to a 
minimum of 18% by the addition of a milk product. This 
process is known as standardizing. Standardizing milk or 
cream means the adjustment of the fat or solids content to a 
certain desired percentage. This is accomplished by the mix¬ 
ing in the proper proportion of two qualities of milk or cream, 
one higher, and the other lower than the desired standard. 

A. Make a test of two lots of milk provided. (One to contain 
over 5% fat and one less.) Record the tests. 

B. By using the Pearson square method calculate the porportion 
of each lot of milk required to make a 5% mixture. 


Tests of originals 

Square 

Proportion of each 

Amt. of each 










. 


The proportion of each is derived by subtracting diagonally 
across the square using the desired standard either as the sub¬ 
trahend or minuend as the case may be. The smaller number 
is always subtracted arithmetically from the larger. 

C. Calculate the amount of each lot necessary to prepare exactly 
100 cc. of a mixture testing 5% fat. 

D. Make an accurate test of the prepared mixture. 

Observations: 


Sample 

Test 

Proportion 

cc. of each 

1 

a 





b 




2 

a 





1) 




3 

a 





b 












































LABORATORY MANUAL 


estions: (1) How many pounds of 3.5% milk would have to be added 
to 95 pounds of 33% cream to make a mixture testing 22% 
fat? 

(2) How many pounds of skimmilk testing 0.0% fat would have 
to be mixed with 35% cream to produce 150 pounds of 22% 
cream? 

(3) How many pounds of 3.2% milk would have to be mixed with 
38% cream to make a mixture testing 25% fat? 

(4) How may pounds of 22% cream can be produced from 5000 
pounds of 3.5% milk? 

Van S. pp. 263-268; Jud pp. 72-76; St. pp. 181-184. 


DAIRY HUSBANDRY 


25 


EXERCISE NO. 16 

Object: To become acquainted with the Sin-acid test for fat in milk. 

Procedure: The sin-acid (without acid) solution is prepared as follows: 

Mix 7 cc. of amyl alcohol with 31 cc. of 95% ethyl alcohol, and 

add the mixture to 64 cc. of 0.8 normal sodium hydroxide solu¬ 
tion. 

A. Test a lot of milk in duplicate by the Babcock method. 

B. Test the same lot of milk by the sin-acid test as follows: 

Method 1. 

(1) Place 17.6 cc. of milk in a 10% milk test bottle and add 
17.5 cc. of sin-acid solution. 

(2) Mix the sample thoroughly with a rotary motion, and 
finally with a churning motion, with the tip of the bottle 
closed with the finger. 

(3) The bottles should then be placed in hot water (190°-200° 
F.) for 10 minutes and again shaken, and filled with hot 
water (190°-200° F.) up to the neck. The bottles are then 
replaced in the water bath (190°-200° F.) for 30 minutes. 
The fat is then brought into the neck by adding hot water 

(190°-200° F.), placed in a water bath at 140° F. for 5 
minutes and then read. 

C. Sin-acid test—Method (2). 

(1) Perform same as 1 and 2 of B above. 

(2) The bottles are placed in a water bath at 190°-200° F. and 
shaken from time to time until the curd is dissolved. 

(3) Place in centrifuge and whirl for 3 minutes; fill with hot 
water (140° F.) into neck, place in water bath at 140° F. 
for 5 minutes and read. 


Observations: 


San 

lple 

%fat 

Color 

Condition 

1 

a 




2 

a 





b 




3 

a 



• 


b 
























26 


LABORATORY MANUAL 


Conclusions: 

Questions: (1) Name at least six tests, other than the Babcock, for 
fat in milk. 

(2) By use of a problem, illustrate that it is incorrect to obtain 
composite samples of milk with a small dipper. 

(3) How should a composite sample of milk be prepared for the 
test? 

(4) What special precautions should be observed when a hand 
tester is used? 

References: F. & W. \\ 179-199, inclusive, f 69, 70, 71; Van pp. 31, 
70-72; St. pp. 112-114. 


DAIRY HUSBANDRY 


EXERCISE NO. 17 

Object: To become, acquainted with the Rose-Gottlieb method for the de¬ 
termination of fat in milk. 

Procedure: The Mojonnier tester, largely used in milk condensing fac¬ 
tories and ice cream factories, is based on the Rose-Gottlieb. 

A. Make a duplicate test of the milk, provided, by the Babcock test. 

B. Pipette 10 grams of the milk provided into a specially con¬ 
structed Rohrig extraction tube, and proceed as follows: 

(1) Add 1 cc. of concentrated ammonia and mix thoroughly. 

(2) Add 10 cc. of 92% ethyl alcohol and mix thoroughly. 

(3) Add 25 cc. of washed ethyl ether and mix thoroughly. 

(4) Add 25 cc. of petroleum ether and mix thoroughly. 

(5) close the tube with a moist stopper and allow to stand for 
6 hours. 

(6) Read at the base of the clear liquid and at the top and 
drain off an aliquot portion of the clear liquid into a clean 
carefully weighed aluminum evaporating dish. 

(7) Evaporate the ether from the dish under a hood, until all 
ether has evaporated. Cool the dish and carefully weigh 
again. The increase in wieght represents the fat in that 
portion of the solution drawn off. The total weight of the 
fat can be calculated and since a 10 gram sample of milk 
was used, it is easy to determine the per cent of fat present. 

Note: The temperature of the hot plate should be in the 
neighborhood of 135° C. (275°F.). 


Observations: 


Sample 

Grams 

milk 

% of ether 
solution 
used 

Weight of 
empty dish 

Weight of 

contents after 
evaporation 

Amt. 

of fat 
present 

1 

a 







b 






2 

a 







b 







Conclusions: 

Questions: (1) How would the Rose-Gottlieb procedure differ, if a sub¬ 
stance high in fat were tested? 

(2) If a patron delivers 525 pounds of milk testing 3.8% and the 
price of butter fat were 42c, what would he receive for the 
milk? 

(3) If the farmer in problem 2 were paid at the rate of 1.80 for 
100 pounds of 3.5% milk and 5c for each .1% above or below 
this test, what would he receive for the milk? 

(4) What would he get for the milk at the rate of $1.50 per 10 gal¬ 
lon can? 

References: F. & W. If 254; Van S. 253-254. 
























28 


LABORATORY MANUAL 


Several exercises are suggested below as substitutes or additions if it is 

felt that a need for such exercises exists. Merely a brief outline, with no 

mention of observations, conclusions, or questions is given. 

EXERCISE NO. 18 

Object: To determine the influence of souring of milk on its fat content. 

Procedure: 

A. Test a lot of milk in duplicate. 

B. Measure out 17.6 cc. of the above lot of milk into each ol two 
10% milk test bottles, and set these aside until the next exer¬ 
cise. 

C. Test the two soured samples of milk by the same method used 
for sample A and compare results. 

References: F. & W. If 32; Van S. p 23; St. p 132 

EXERCISE NO. 19 

Object: To determine the variation in the fat content of the milk of one cow 
during various stages in the milking process. 

Procedure: 

A. Strip some of the first milk from each of the four quarters into 
a sample bottle. Label properly. 

B. Repeat this with another bottle when one-half through milk¬ 
ing. Label. 

C. Strip the last milk from each of the four quarters into a third 
bottle. Label. 

D. Test each of the above samples in duplicate. 

References: F. & W. If 168; Van S. p. 8; Jud. p. 35; St. pp. 49-51. 

EXERCISE NO. 20 

Object: To determine the variation in the fat content of milk of one cow from 
one milking to another. 

Procedure: Obtain a representative sample of milk from each of six 
milkings of one cow and test each sample in duplicate. 

References: F. & W. If 160-164 inclusive. Van S. p. 7; Jud. pp 35-38, St. 
p 48. 


DAIRY HUSBANDRY 


29 


SERIES C. 

Testing cream for fat 

Materials necessary for 10 students: 

100 cc. glymol or “red reader .” 

EXERCISE NO. 21 

Object: To become acquainted with one method of testing cream with the Bab¬ 
cock test. 

Procedure: “Cream may be tested by the Babcock test in the same man¬ 
ner as milk, and the results obtained are accurate when neces¬ 
sary care has been taken in sampling the cream and measuring 
the fat.” (F. & W. H 85.) 

A. Carefully balance a 30% cream test bottle on the balances 
provided. 

B. Weigh out exactly 18 grams of a well mixed lot of cream. 
Make all tests in duplicate. Add approximately 16 cc. of sul¬ 
furic acid and test as whole milk. 

C. Place the bottles in a hot water bath (135°-140° F.) for 5 min¬ 
utes and read immediately by including all of the lower 
menicus and one-third of the upper meniscus. 

D. Replace bottles in the water bath for 5 minutes, and add a few 
drops of glymol (colored Petrolatum) and read, including both 
extremes of the fat column. 


Observations: 


Sample 

%fat 

Color 

Condition 

1 

a 




b 




2 

a 




b 





Conclusion: 

Questions: (1) What is the size of the smallest graduation on the neck 
of a 30%, 6-inch, 18 gram test bottle? 

(2) What is the object of using glymol or “red reader” before read¬ 
ing cream tests? 

(2) When should glymol be added to the fat column? 

(4) How should cream tests be read without glymol? Outline the 
various suggestions. 

References: F. & W. If 85-89 inclusive; Van S. pp 73-92; Jud. pp 75-85; 
St. pp 119-128. 























30 


LABORATORY MANUAL 


EXERCISE NO. 22 

Object: To demonstrate the fallacy of testing cream by volume. 

Procedure: “Several factors tend to render inaccurate the measuring of 
cream for the Babcock test, and correct results can therefore 

only be obtained by weighing the cream.” (F. & W. % 86). 

A. Test a sample in duplicate as in exercise 21. 

B. Measure out a 17.6 cc. sample of the above cream into each of 
two cream test bottles and complete the test in the usual man¬ 
ner. 

Note: In case the 9 gram sample is the legal sample, weigh 
out 9 grams of cream under A above, add about 9 cc. ol water 
and mix. Then add 17.5 cc. of sulfuric acid, mix, and test as in 
Exercise 21. 


Observations: 


Sample 

% fat 

Color 

Condition 

1 

a 





b 




2 

a 





b 





Conclusion: 

Questions: (1) Give three reasons why the cream samples should be 
weighed rather than measured with a pipette. 

(2) Give a table of figures to show how the richness of cream influ¬ 
ences its weight. 

(3) Explain the use of, and describe the construction of the Wis¬ 
consin hydrostatic cream balance. 

(4) Give a formula for calculating the test of a sample of cream 
if less than 18 grams are used in an 18 gram test bottle. 

References: F. & W. H 85-89 inclusive; Van S. pp 73-92; Jud. pp 75-85; 
St. pp 119-128. 




















DAIRY HUSBANDRY 


31 


EXERCISE NO. 23 

Object: To determine the accuracy of using various weights of cream for the 
Babcock test. 

Procedure: “The smaller the quantity of cream taken for a sample the 
greater is the error introduced by inaccurate weighings or 
readings. The result is rendered more accurately if two or three 
tests of a sample are made and the readings averaged.” (F. & 
W. If 91.) 

A. Accurately weigh out 18 grams of cream into each of two cream 
test bottles and test as in exercise 21. 

B. Accurately weigh out 9 or 10 grams of cream into each of two 
cream test bottles and use sulfuric acid in proportion. Then 
complete the tests as for part A. The per cent of fat may 
be calculated by the following formula. 

18 X Reading — _ %fat 
grams cream used 

Note: Any weight of cream from 3 grams up may be used. 


Observations: 


Sample 

Reading 

% fat 

Color 

Condition 

1 

a 






b 





2 

a 






b 






Conclusion: 

Questions: (1) Explain how a sample of cream may be tested by using 
10% milk test bottles. 

(2) What is the legal standard in Wisconsin for fat in cream? 

(3) If the weight of a 10 gallon can of water is 83.3 pounds, what 
would be the weight of a 10 gallon can of 25% cream? 20% 
cream? 

(4) If 295 pounds of cream test 33% fat, how many pounds of fat 
does it contain? 

References: F. &. W. ^f 85—96 inclusive, 305, 307, Table X\ I, Van S. 
pp 73-92, Jud pp 75-85; St. pp 119-128. 




















32 


LABORATORY MANUAL 


EXERCISE NO. 24 

Object: To compare several methods of treating the cream sample during the 
testing process. 

Procedure: In factories where the aim is speed of operation, certain-so- 
called short cuts have been adopted, which, if carefully used 
will give good results. 

A. Accurately weigh out 18 grams of cream into each of two 
cream test bottles, and test as in exercise 21, using less than 
17.5 cc. of sulfuric acid. 

B. Accurately weigh out 18 grams of cream, in each of two cream 
test bottles,, add 17.5 cc. of acid to each and mix thoroughly. 
Then add lukewarm water (80°-90° F..) up to the neck and 
whirl for five minutes and after filling with water, again for one 
minute. 

C. Accurately weigh out 9 grams of cream into each of two cream 
test bottles, add an equal quantity of water at room tempera¬ 
ture. Then add 17.5 cc. of acid and test as A above. Calcu¬ 
late the test. 


Observations: 


Sample 

Weight of 
Sample 

Reading 

% fat 

Color 

Condition 

1 

a 





/ 

b 






2 

a 






b 






3 

a 






b 







Conclusions: 


Questions: (1) If a 7.5 gram sample of cream gives a reading of 15.5% 
what is the test of the cream? 

(2) How are cream test samples handled for cream that is gathered 
on the route in large cans? 

(3) What advantages has gathering cream in the patron’s own 
cans over mixing the cream from all patrons on the route? 

(4) Name at least 3 types of cream scales and give the advantages 
and disadvantages of each. 

References: F. & W. ^ 91, 200-211 inclusive; Van S. pp 73-92; Jud. pp 
46-52, 75-85; St. pp 119-128. 


































DATRY HUSBANDRY 


33 


SERIES D. 

Testing Skimmilk, Buttermilk, ami Whey for Fat. 

Materials necessary for 10 students: 

20—Double necked test bottles graduated in .01 % up to .5%. 

5 —25 cc. graduated cylinders. 

EXERCISE NO. 25 

Object: To lest skimmilk for fat using two different quantities of acid and 
varying whirling time. 

Procedure: It has been found that if a sample ot skimmilk is tested for 
fat as whole milk is tested, the result will be much less than 
the actual amount of fat present. 

A. After thoroughly mixing the sample of skimmilk, measure out 

17.6 cc. into a double necked bottle, add 17.5 cc. of sulfuric 
acid, mix, and whirl as for whole milk. Read without a water 
hath. « 

B. Obtain a 17.6 cc. sample as above, but add at least 22 cc. of 
sulfuric acid in two portions, mixing thoroughly after each 
addition. Whirl at the usual speed as follows: 15-3-2. 

C. Use whole milk test bottles and add 17.5 cc. of acid to 17.6 cc. 
of skimmilk and complete the test as for whole milk. 

Observations: 


Sam 

iple 

cc. acid 

Time of 
Whirling 

% fat 

Color 

Condition 

1 

a 






b 






2 

a 






b 






3 

a 






b 







Conclusion: 

Questions: (1) Why are double necked bottles to be placed with the 
fdling tube toward the center of the tester? 

(2) What reason can be given for the fact that not all of the fat 
gathers in the neck of the bottle when skimmilk is tested for 
fat? 

(3) If a separator leaves .2% fat in the skimmilk, how much fat 
would be lost in 2855 pounds of skimmilk? 

(4) Why should a sample of skimmilk not be pipetted into the 
test bottle immediately after separating? 

References: F. & W. f 97, 98, 99, 100; Van S. pp. 93-95; Jud p. 85; St. 
pp. 129-130. 






















34 


LABORATORY MANUAL 


EXERCISE NO. 26 

Object: To become acquainted with the Babcock test for fat in buttermilk. 

Procedure: The general opinion among creamery operators has been that 
the loss of fat in buttermilk did not exceed .2%. Recent inves¬ 
tigations, however, have disclosed the fact that the loss rarely 
is less than .4%. The amount lost depends greatly on the 
methods of handling the cream and the churns. 

A. Thoroughly mix a sample of butter milk. Rapidly pipette 
17.6 cc. into a double necked bottle and add 20 cc. of acid. 
Mix well. Whirl a total of 10 minutes in three steps. 

B. Measure out 17.6 cc, of buttermilk into a second double necked 
bottle and add at least 22-25 cc. of sulfuric acid in two portions, 
mixing carefully after each addition. Whirl in a hot tester as 
follows: 15-3-2. 

C. Repeat “A” above by using an 8.8 cc. sample of buttermilk 
and 10 cc. of sulfuric acid. 

D. Repeat “B” above by using an 8.8 cc. sample and at least 11- 
13 cc. of acid and whirling in a hot tester 15-3-2. 

E. Test one 17.6 cc. sample of buttermilk in a whole milk test 
bottle. Use 20 cc. of acid and whirl a total of 20 minutes. 

Note: Method “A” is the old recommended method by which 
results below .2% were usually obtained, while method “B” 
and “D” are the improved methods by which results within 
.1% of actual gravimetric analysis are obtained. 


Observations: 


Sample 

cc. 

Butter 

milk 

cc. acid 

Length 

whirling 

% fat 

Color Condition 

1 

17.6 


10 



2 

17.6 


20 



3 

8.8 


10 



4 

8.8 


20 



5 

17.6 


20 




Conclusions: 


Questions: (l)The fat test of 150 pounds of whole milk is 3.4%, and 
the fat test of 128 pounds of skimmilk from this milk is .04%. 
What should be the approximate test of the cream? 

(2) Briefly describe the Association test for fat in buttermilk. 





















DAIRY HUSBANDRY 


35 


(3) It is generally assumed that the weight of the buttermilk ob¬ 
tained is equal to the pounds cream minus the pounds butter- 
fat. If 610 pounds butter are produced from 2000 pounds of 
cream testing 25% fat and the test of the buttermilk is .4% 
what is the per cent fat in the butter? 

(4) How many pounds ol fat were lost in the buttermilk in pro¬ 
blem (3)? 

References: F. & W. f 101; Van S. pp. 93-95; Jud. pp. 85-86; St. pp. 
129-130. 


36 


LABORATORY MANUAL 


EXERCISE NO. 27 

Object: To test a sample of whey for fat by the Babcock test. 

Procedure: The fat in the whey when cheese is made usually varies 
from about .4% to over 1.0%. However, most of this fat can 
be recovered by running the whey through a specially con¬ 
structed separator. 

A. Measure out 17.6 cc. of a well mixed sample of whey into a 

double necked bottle, and add 10-15 cc. of sulfuric acid. Mix 
and whirl a total of 10 minutes. r % | 

B. Measure out an 8.8 cc. sample of whey and add 5-7 cc. of acid, 
mix and proceed as for “A” above. 

C. Measure out a 17.6 cc. sample of well mixed whey into a whole 
milk test bottle and proceed exactly as for “A” above. 


Observations: 


Sample 

cc. Whey 

cc. Acid 

% fat 

Color 

Condition 

1 






2 






3 







Conclusions: 


Questions: (1) Why is more acid required for testing skimmilk and but¬ 
termilk, and less when testing whey than for whole milk? 

(2) What other constituents besides fat are found in whey? 

(3) How does whey compare in feeding value with skimmilk and 
butterfat? 

(4) What is skimmilk worth for hog feed when compared with 
corn, or hogs per pound live weight? 


References: F. & W. If 101; Van S. pp. 93-95; 16; Jud. p. 86. 















DAIRY HUSBANDRY 


37 


SERIES E. 

Use of the Lactometer. 

Ma terials necessary for 10 students. 

2—Pounds butter salt (best grade). 

1—gallon distilled water. 

EXERCISE NO. 28 

Object: To test the accuracy of a lactometer. 

Procedure: When a new lactometer is purchased and no tested lactome¬ 
ters are available for checking the accuracy of the new one, 
it may be necessary to use some other method for checking. 

A. Place exactly 300 cc. of distilled water into each of 3 containers 
labeled A, B, and C respectively. To cylinder A, add 9 grams 
of pure dairy salt, to B, add 12 grams of pure dairy salt, and to 
C add 15 grams of pure dairy salt. Allow the salt to dissolve 
and bring the mixture to exactly 60° F. 

R. Insert the lactometer to be tested successively into each of the 
three solutions, A, B, and C, carefully wiping the lactometer 
before each insertion. The readings on the lactometer should 
indicate 1.022, 1.029, and 1.036 specific gravity respectively 
for A, B, and C. 

Note: Be sure to have the solution well mixed before insert¬ 
ing the lactometer. 

Observations: 


Salt solution 

Correct reading 

Lactometer reading 

Error 

A 

1.022 



B 

1.029 



C 

1.036 




Conclusion: 

Questions: (1) Define the term specific gravity. 

(2) What is the object of knowing the specific giavity of certain 
lots of milk? 

(3) What is a lactometer, and on what principal is it based. 

(4) Describe fully the markings on the neck of a Quevene lac¬ 
tometer. 

Reference: F. & W. If 109, 110, 118, 118a; Van S. pp. 175-179; Jud. pp. 
91-101; St. pp. 136-143. 














38 


LABORATORY MANUAL 


EXERCISE NO. 29 

Object: To become acquainted with the use oj the Quevene lactometer for deter¬ 
mining the specific gravity, the solids not fat, the total solids, and 
the specific gravity of total solids of milk. 

Procedure: The normal specific gravity of cow’s milk varies from 1.029- 
1.035 at 60° F., the average being about 1.032. The solids no 
fat (S N F) range slightly above 8.5%, and the total solids 
(T S) is equivalent to the S N F p ] us the fat. The specific 
gravity of T S varies from 1.25-1.34, usually averaging above 
1.30. The addition of a foreign substance or the removal of a 
constituent of milk will usually effect one or more of the above 
constituents, hence a knowledge of lactometer work aids in the 
detection of adulterations. 

A. Mix a sample of milk thoroughly and obtain a 17.6 cc. sample 
for a fat determination. Fill the glass lactometer cylinder 
with milk and insert the lactometer. Allow the lactometer to 
come to rest and read the temperature. If it is above 70° F. 
or below 50° F. cool or warm the sample as necessary. If the 
temperature is within the range given, read the point on the 
lactometer scale to which it has sunken. 

B. Make temperature corrections (F. & W. If 111, 112, 113). 

C. Make calculations necessary to fill in data required under ob¬ 
servations. 

Note: See F. & W. If 118 for cleaning lactometer, and be 
sure the lactometer is dry before it is inserted in the milk. 

Observations: 


Sam¬ 

ple 

% 

fat 

Lact. 

reading 

Temper¬ 

ature 

Corrected 

reading 

% 

SNF 

% 

TS 

Sp. gr. 
of milk 

Sp. gr. 
of solids 

1 









2 










Conclusions: 

Questions: (1) Why is it not possible to obtain the specific gravity of 
milk immediately after milking? 

(2) Why should the lactometer reading be taken immediately after 
the milk is mixed and the lactometer inserted? 

(3) How should the lactometer be read with reference to the 
meniscus? 

(4) Give the formulae for determining the SNF, TS, and the spe¬ 
cific gravity of TS. 

References: F. & W. If 109-121, inclusive, 125; Van S. pp. 175-196; Jud. 
pp. 91-101; St. pp. 136-143. 


















DAIRY HUSBANDRY 


39 


EXERCISE NO. 30 

Object: To become acquainted with adulteration formulae and their verifica¬ 
tion. 

Procedure: A number of formulae have been developed for calculating 
the extent of adulteration, if skimming or watering, or both 
have been practiced. 

A. Obtain the lactometer reading and the fat test of a one pint 
sample of normal milk. 

B. Divide the pint of milk into two equal parts and proceed as 
follows: 

(1) Add water to one part at the rate of 5 cc. per 100 cc. of 
milk, and test as “A” above. 

(a) On the basis of the control sample, calculate the per 
cent of water added to the original milk by the following 
formula: 

100 X control for SNF 

-100 

SNF in suspected sample 

(b) On the basis of the legal standard for SNF, calculate 
the per cent of water added to the original milk by the 

following formula: 
lOOXleg. standard for SNF 

--- 100 . 

SNF in suspected sample 

(c) Add skimmilk, a little at a time, from a graduate until 
the lactometer is again as in A above. Record the 
amount of skimmilk used. 

(2) To the second half pint add water at the rate of 10 cc. per 
100 cc. of milk and proceed exactly as for the first pint. 


Observations: 


Sample 

% 

fat 

Corrected 

Lactom¬ 

eter 

reading 

% 

SNF 

% 

water 

added 

cc. skim¬ 
milk 
added 

% adull 

teration 

Formula 

A 

Formula 

B 

1 









2 

a 









b 








3 

a 









b 









Conclusion: 




































40 


LABORATORY MANUAL 


Questions: (1) What is meant by the term “control sample” when we 
refer to testing milk for total solids? 

(2) What is the legal standard for SNF of cow’s milk? 

(3) What effect on the lactometer will the addition of preservatives 
have? How may this difficulty be overcome? 

(4) How does the New York board of Health lactometer differ 
from the Quevene? How may the readings of one be converted 
to those of the other? 

References: F. & W. If 114, 117, 127; Van S. pp. 175—188; Jud. pp. 91—101; 
St. pp. 136-143. 


DAIRY HUSBANDRY 


EXERCISE NO. 31 


Object: To determine the adulteration of an unknown sample of milk. 


Procedure: The table of adulteration which follows is to be compared 
with the control sample if one is provided or it may be used 
with the factors usually assigned to normal milk. 



Normal 

Watered 

Skimmed 

Skimmed and 

W atered 

Fat 

3% + 

Lower 

Lower 

Lower 

Sp. Gr. of 
milk 

1.029—1.035 

Lower 

Higher 

Normal—higher 
or lower 

% S. N. F. 

8.5% + 

Lower 

Nor. or higher 

Lower 

% T. S. 

11.5% + 

Lower 

Lower 

Lower 

Sp. Gr. of 
milk solids 

1.25—1.34 

Normal 

Higher 

Higher 


A. Make a lactometer and fat test of the control sample and in¬ 
clude all calculations. 

B. By using the Babcock test and the lactometer, analyze the 
“adulterated” sample of milk and report the adulteration. 

C. Calculate the per cent reduction of SNF by the following for¬ 
mula: 

SNF in control—SNF in adulterated 


D. 


-xioo. 

SNF in control 

Calculate the per cent reduction of fat by the following for¬ 
mula: 

% Fat in control—% in adulterated 

--xioo. 


% Fat in control 

If the sample is watered only the two results obtained should 
correspond. If the sample is skimmed only, no appreciable 
answer will be obtained from the 1st formula. Usually the 
answer is negative. If an appreciable answer is obtained from 
the first formula, and if the result from the last formula is 
greater than that from the first, the sample is Watered and 
Skimmed. The difference between the two results gives the % 
of skimming. 


















42 


LABORATORY MANUAL 


Observations: 


Sample 

Fat 

Sp. Gr. 
of milk 

SNF 

TS 

Sp. Gr. 
of solids 

Adultera¬ 

tion 

% adultera¬ 
tion 

1 








2 









Conclusions: 

Questions: (1) What is the per cent SNF and what is the condition of 
each of the following samples of milk when compared with the 
table given? 

(a) 32.0 at 58° F. 4.0% fat 

(b) 33.5 at 56° F. 2.5% fat 

(c) 30.0 at 63° F. 3.5% fat 

(d) 28.0 at 54° F. 2.5% fat 

(e) 27.4 at 69° F. 2.4% fat 

(2) How does the SNF content of milk vary with the fat content? 

(3) What is the specific gravity of pure butter fat at 135°-140°F.? 

(4) How can cheese yield be calculated when using the Babcock 
test and the lactometer? 

References: F. & W. Tf 121-126,inclusive, 224; Van S. pp. 175-189; Jud. 
pp. 91-101; St. pp. 136-143. 

















DAIRY HUSBANDRY 


43 


SERIES F. 

Acidity Determination of Dairy Products. 

Materials necessary for 10 students: 

30—Grams sodium hydroxide ( NaOH ). 

100 — cc. phenolphtalein solution ( indicator). 

1000—Farrington alkaline tablets. 

500 —cc.Vio normal oxalic acid solution {prepared by adding 500 
cc. of distilled water to 3.151 grams C. P. oxalic acid 
crystals {HiCfO\.2 H 2 0.) 

10—25 cc. pipettes. 

10—Small dippers {20 gauge shot gun shell size). 

5—5 gram weights. 

10 — 500-1000 cc. reagent bottles. 

5 — Kg. distilled water. 

EXERCISE NO. 32 

Object: To become acquainted with the preparation of a l /i 0 normal sodium 
hydroxide solution, and of a standard Farrington Alkaline Tablet 
Solution. 

Procedure: In preparing solutions for acidity testing, it is essential that 
there be a standard strength to work on. The standard 
adopted is the normal solution. 

A normal solution of an acid is one which, approximately 
speaking, contains 1.0 grams of replaceable hydrogen per liter 
of solution, and a normal solution of an alkali is one that will 
just neutralize a normal solution of an acid volume for volume. 
Another definition of a normal solution is as follows: A normal 
solution is one which contains the molecular weight of the ma¬ 
terial divided by the hydrogen equivalent of the active ele¬ 
ment, dissolved and diluted to a liter. Consequently a normal 
solution of an alkali is a solution that contains the chemical 
equivalent of 1.0 grams of replaceable hydrogen per liter. 

More accurate work can be done with weak solutions, hence 
it is customary to prepare n /i 0 solutions of an alkali for titrating 
the acidity of milk. 

A. To prepare a 1 /i 0 normal( n /i 0 )sodium hydroxide (NaOH) solution 
proceed as follows: 

(1) Carefully balance a clean dry stoppered test tube on an or¬ 
dinary butter or cheese moisture test scale. 

(2) Place a piece (2-4 grams) of NaOH in the test tube, stop¬ 
per tightly, and obtain the exact weight of the NaOH. 
Transfer the NaOH to a clean bottle. Calculate the vol¬ 
ume to which to dilute with distilled water to make an n /i 0 
solution as follows: 

grams NaOH X1000 

---= Total volume of solution 

4 

Rinse out the test tube into the bottle. 



44 


LABORATORY MANUAL 


(3) Allow the NaOH to dissolve, mix well and place at least 
20 cc. of the solution in a thoroughly cleaned graduated 
burette. 

(4) Measure out exactly 17.6 cc. of a prepared n /i 0 oxalic acid 
solution into a clean white cup. Add two drops of phenolph- 
talein indicator prepared according to F. & W. If 131. 
Titrate this against the NaOH solution in the burette. 
If exactly 17.6 cc. of NaOH solution produces a faint pink 
color, the NaOH solution is exactly n /i 0 . If more than 17.6 
cc. are required, it is too weak. If less is required, it is too 
strong. From the actual amount required, it is possible to 
calculate the amount of additional water or NaOH re¬ 
quired to make it the proper strength. 

B. To prepare an %<> Farrington alkali table solution. 

( 1 ) Measure out a definite quantity of distilled water into a 
clean bottle and calculate the number of Farrington alka¬ 
line tablets to add as follows: 

cc. water used X 25 

-= number of tablets necessary. 

97 

The rule for preparing an n /io solution is to use 25 tablets to 
97 cc. of water. 

Note: The Standard Farrington alkaline tablet solution 
is prepared by using 5 tablets to 97 cc. of water. An n /i 0 
Oxalic acid solution is prepared by weighing out 6.3 
grams of oxalic acid crystals (H 2 C 2 O 4 . 2 H 2 O) and add 
enough distilled water to make 1000 cc. 

Observations: 





Grams NaOH or 



cc. Water 

number of tablets 


NaOH solution 




Farrington’s 




Notes on preparation. 

Conclusion: 


Questions: (1) How should an n /i 0 KOH solution be prepared? 

(2) What is the strength of a Standard Farrington alkaline tablet 
Solution? 

(3) Explain in detail why 6.3 grams of C. P. oxalic acid crystals are 
used to make up an n / l0 solution? 

(4) Why is sulfuric acid not used for making n /i 0 solutions? 

References: F. & W. If 128-141, inclusive; Van S. 131-139; Jud. pp. 102- 
106; St. pp. 132-136. 














DAIRY HUSBANDRY 


45 


EXERCISE NO. 33 

Object: To lest several lots of milk for acidity , using the n /i C NaOH solution 
( Mann’s test ) and various sized pipettes. 

Procedure: An acidity test is useful when: 

(1) Grading milk or cream at the receiving room. 

(2) Ripening cream for butter making. 

(3) Making cheese. 

(4) Bottling milk or cream in a city milk plant. 

(5) Condensing milk. 

(6) Making cultured milks. 

(7) Manufacturing casein. 

A. With an 8.8 cc. pipette measure out 8.8 cc. of well mixed milk 
from lot Number 1, into a clean white cup. Add one drop of 
phenolphtalein indicator and from a burette graduated to 
tenths of a cc., and while stirring the milk continuously, add 
enough n / 10 NaOH solution to produce a permanent faint pink 
color. Each cc. of NaOH solution used indicates .1% acidity. 

B. Use a 17.6 cc. pipette for measuring out a sample of the same 
lot of milk used for A and proceed as above. Use two drops 
of phenolphtalein indicator. Record the number of cc. of n / 10 
NaOH solution used and calculate the per cent of acidity 
present by using the following formula: 

cc. n /i 0 NaOH X-009 XlOO 

-= % acidity. 

cc. sample 

C. Use a 25 cc. sample of the same milk and proceed as in above. 

D. Perform the above three operations on each of the lots of milk 
provided. 




46 


LABORATORY MANUAL 


Observations: 


Sample 

cc. milk 

cc. n /i 0 NaOH 

% acidity 

1 

a 




b 




c 




2 

a 




b 




c 



' 

3 

a 




b 




c 





Conclusions: 

Questions: (1) What will be the effect if a bottle of NaOH solution is 
left unstoppered? 

(2) What is the cause of acidity in milk? What is the average 
acidity of fresh milk? 

(3) How is the phenolphtalein indicator solution prepared? 

(4) If 20 cc. of cream require 15 cc. n / i0 NaOH solution for neutrali¬ 
zation, what is the per cent acid in the sample? 


References: F. & W. ^ 128-152, inclusive; Van S. 131-151; Jud. pp. 
102-106; St. pp. 132-136. 

























DAIRY HUSBANDRY 


47 


EXERCISE NO. 34 

Object: 7 o compare Mann’s and theFarrington Alkaline Tablet acidity tests. 

Procedure: A Standard Farrington Alkaline tablet solution is prepared 
by dissolving 5 tablets in 97 cc. of water. The strength of this 
solution should be such that if an 18 gram (17.6 cc.) sample of 
milk is used, 1 cc. of the solution will indicate exactly .01% 
acidity. If 97 cc. of the solution were necessary to produce a 
faint pink color in an 18 gram sample, there would then be 
present .97% lactic acid or 18X.0097 =.1746grams of lactic 
acid would be present in the 18 gram sample. Since 5 tablets 
were used in preparing the 97 cc. each tablet will neutralize 
.1746 -T- 5 = .03492 grams of lactic acid. Since there is one 
tablet in 19.4 cc. of water, each cc. of the Standard solution 
will neutralize .0018 grams of lactic acid. Therefore .0018 -5- 
.09 = .02 = 2 /ioo or the solution is 1 / 60 normal. This illustration 
shows how it is possible to prepare a solution of any desired 
strength. 

A. Use any of the three methods outlined in Exercise 33, Series F, 
and test in duplicate by the Mann’s test each of the lots of 
milk provided. 

B. With a pipette measure out 17.6 cc. of the milk to be tested 
into a white cup. Use a 100 cc. graduate containing the 
Standard Farrington Alkaline tablet solution, and continue add¬ 
ing small quantities of the solution to the milk until a faint 
pink color develops. Record the number of cc. of the solution 
used. The milk in the cup should be stirred continuously while 
the Farrington alkaline tablet solution is being added. 

C. Test each of the lots of milk provided by both of the above 
methods. All tests should be made in duplicate. 

Observations: 


Test 


cc. sample 

cc. solution 

% acidity 

Mann’s 

a 




b 




Farrington’s 

a 




b 





Conclusions: 

Questions: (1) What are the advantages and disadvantages of the Far¬ 
rington Alkaline tablet solution and the NaOH solutions? 

(2) What influence has the richness of cream on the acidity test? 

(3) If a 40% fat cream contains .20% acidity, what is the acidity 
of the serum? 

(4) If cream testing 25% fat has an acidity of .5%, what will be the 
“corresponding” acidity of cream testing 40% fat? 

References: F. & W. If 135-151, inclusive; Van S. pp. 131-151; Jud. pp. 
102-111; St. pp. 132-136. 














48 


LABORATORY MANUAL 


EXERCISE NO. 35 

Object: To become acquainted with the preparation and use of the Farrington 
rapid method of acidity testing. 

Procedure: Milk which gives the highest acid test contains, as a rule, 
a larger number of bacteria and spores not destroyed by pas¬ 
teurization than does milk giving a low acid test. (F. & W. 
If 129.) It is therefore important that milk be properly se¬ 
lected at the receiving room in order to have the best material 
for manufacturing purposes, and any simple test which will 
aid in the proper selection is of immense value. 

A. The Farrington rapid method alkaline tablet solution for se¬ 
lecting milk containing less than .2% acid, is prepared by dis¬ 
solving two Farrington alkaline tablets in one ounce of distilled 
water. This solution is ready for use after about 12 hours, or 
after all tablets have entirely disentegrated. 

If, when equal amounts of this solution and milk are taken 
and mixed, the mixture turns pink, the per cent is below 
.2%. Conversely, if the mixture remains white, the acidity is 
above .2%. 

B. Test all samples provided, using the dippers and cups supplied. 

Note: With a little practice in using fractional parts of a dip¬ 
per of solution, the approximate acidity of a sample may be 
determined. 


Observations: 


Sample 

Approximate acidity 

1 


2 


3 



Conclusions: 

Questions: (1) How is an NaOH solution, equal in strength to the Far¬ 
rington rapid method solution, prepared? 

(2) How is a Farrington alkaline tablet solution prepared so that 
it will indicate an acidity exceeding .25%? 

(3) If 25 cc. of milk requires 5 cc. of an n / # NaOH solution for 
neutralization, what per cent of acidity does milk contain? 

(4) If 20 cc. of an n / 9 NaOH solution is necessary to neutralize a 
17.6 cc. sample of milk, what per cent acidity has it? 

References: F. & W. If 128-150, inclusive; Van S. pp. 131-151; Jud pp 
102-111; St. pp. 132-136. 















DAIRY HUSBANDRY 


49 


SERIES G. 

Testing Milk for Casein. 

Materials necessary for 10 students: 

*1— Hart casein centrifuge ( 15 " diameter, tubes extended). 

*20 — Hart casein test bottles. 

5—20 cc. pipettes. 

5—10 cc. pipettes. 

5—5 cc. pipettes. 

5—1 cc. pipettes. 

*100 cc. — Chloroform. 

*500 cc.—.25 % acetic acid solution (10 cc. glacial acetic acid diluted to 
100 cc. with water: then diluting 25 cc. of this solution to 
1000 cc). 

5—200 cc. flasks. 

*500 cc.—Standard NaOH solution (795 cc. n /io NaOH solution plus 
distilled water to equal 1000 cc). 

*25—Filter paper discs 6". 

*500 cc .— n / 9 NaOH solution. 

*200 cc. — 40% formaldehyde (neutral). 

3000 cc—Distilled water. 

5 — 4" glass funnels. 

EXERCISE NO. 36 

Object: To become acquainted with the Hart Casein Test. 

Procedure: The casein content of milk averages between 2.0 and 4.0%, 
and is equal to about 80% of the proteins present. Its per¬ 
centage composition is approximately, carbon 53.0%; hydro¬ 
gen 7.12%; nitrogen, 15.65%; oxygen, 22.6%; Sulphur, 
0.78%; phosphorous, 0.85%. It forms about 20-25% of the 
total solids of milk. The ratio of casein to fat varies from 
1:1.9 to 1:1.3. 

Observe the table given below: 

Breed Authority Casein Fat 

Holstein.(Hart. 1 : 1.49 

) Eckles & Shaw. 1 : . 1.31 

Ayrshire.(Hart. 1 : 1.44 

'.Eckles & Shaw. 1 : 1.36 

Jersey.jHart. 1 : 1.72 

\ Eckles & Shaw. 1 : 1.69 

Guernsey. Hart. 1 : 1.90 

Shorthorn. Eckles & Shaw. 1 : 1.36 

A. Test each of the lots of milk provided in duplicate as follows: 
(1) Measure 2 cc. (up to the 4% mark) of chloroform into a 
Hart casein test bottle. Add 20cc. of the prepared .25% 
acetic acid solution at room temperature. Add 5 cc. of the 
well mixed sample of milk. Hold thumb over opening of 
bottle and shake carefully for 20 seconds. Place bottles 
















50 


LABORATORY MANUAL 


in tester in pocket provided with corks and whirl for 8 
minutes at a speed of 57 turns of crank per minute. (2000 
R. P. M.) Place tests in rack for 10 minutes and then 
read results direct. 

B. Make a fat test of the milk provided and compare the ratio of 
the casein to fat. 

Note: All operations for the casein test should be as near 70° 
F. as possible. 


Observations: 


Sample 

% casein 

% fat 

Ratio 1 :? 

1 




2 





Conclusions: 

Questions: (1) What is the condition of the casein in normal cow s milk? 

(2) In what manufactured dairy product is casein one of the chief 
constituents? About what per cent? 

(3) Give a formula and explain its use for determining the approxi¬ 
mate protein and casein content of milk, when the lactometer 
is used. 

(4) What are some of the commercial uses of casein? 

References: F. & W. If 257a, 258, 307; Van S. pp. 8-12, 199-200; St. pp. 
318-321. 















DAIRY HUSBANDRY 


51 


EXERCISE NO. 37 

Object: To become acquainted, with Walker’s Formaldehyde solution method 
of casein determination. 

Procedure: It is important that the formaldehyde used in this test be 
neutralized with alkali before using; i. e., it must have a dis¬ 
tinct pink color to show that it is neutralized. 

A. Test each of the lots of milk provided in duplicate as follows: 

(1) Pipette 10 cc. of a well mixed sample of milk into a porce¬ 
lain cup, add 1 cc. of a one per cent solution of phenolphta- 
lein; neutralize with an n / 9 NaOH solution, stirring con¬ 
stantly until a fairly permanent deep pink color develops. 

(2) Add 2—3 cc. of natural 40% formaldehyde. 

(3) Titrate with n / 9 NaOH solution until the same permanent 
deep color develops as before adding the neutral formalde¬ 
hyde. 

(4) The number of cc. n / 9 NaOH solution used for step 3 mul¬ 
tiplied by 1.63 will give the per cent casein in the sample. 

B. Make a fat test of the milk provided and compare the ratio of 
the casein to the fat. 

Observations: 


Sample 

% casein 

% fat 

Ratio 1 : ? 

l 




2 





Conclusions: 

Questions: (1) If you assume that 17.5 cc. of milk was used instead of 10 
cc. what factor would you use? 

(2) What factor would you use if you have an n /i 0 normal solution 
instead ol an n / 9 solution? 

(3) How may casein be prepared commercially? 

(4) What chemicals are used for precipitating casein? 


References: F. & W. IT 18. 











52 


LABORATORY MANUAL 


EXERCISE NO. 38 

Object: To become acquainted with Van Slyke’s Volumetric method of casein 
determination. 

Procedure: The milk constituents which determine the yield of cheese 
are fat and casein. Since the casein in different milks does not 
increase in as great a ratio as the fat content, a problem arises 
as to the proper method of payment at cheese factories where 
milk having a wide range in fat content is sold. Several sug¬ 
gested methods are: Fat +2; Fat +.6; Fat +calculated casein. 

A. Test each of the lots of milk provided in duplicate as follow: 

(1) Measure out 17.5 cc. of milk into a 200 cc. flask, and add 80 cc. 
of distilled water and 1 cc. phenolphtalein solution. Titrate 
carefully with a standard NaOH solution, shaking vigorously 
after each addition until just a permanent pink tinting of the 
milk is obtained. 

(2) Add standard acetic acid solution in 5 cc. quantities until 25 cc. 
have been added. Shake thoroughly after each addition. If 
the casein does not settle readily, add more acetic acid in quan¬ 
tities of 1 cc. and shake. Record the cc. of acetic acid use as 
“A.” 

(3) Fill the flask with distilled water to the 200 cc. mark. Shake 
10-15 seconds and filter through a dry filter into a dry cup. 
The filtrate should be clear. 

(4) Take 100 cc. of the filtrate and titrate carefully with a standard 
NaOH solution until a permanent pink color which will remain 
a half minute or so, is obtained. Record the cc. of the standard 
NaOH solution as “B.” 

(5) Calculate the per cent casein in the milk by the following 
formula: 

A 

-B = % casein. 

2 

B. Make a fat test of the milk provided and compare the ratio of 
the casein to the fat. 

Observations: 


Sample 

% Casein 

% Fat 

Ratio 1 : ? 

1 




2 





Conclusions: 

Questions: (1) How does the casein content of buttermilk and skimmilk 


compare with that of whey? 

(2) What effect has freezing on the physical and chemical prop¬ 
erties of milk? 

(3) How does casein compare in food value with fat? With sugar? 

(4) W hat part of milk is albumen, and of what commercial value 
is it? 

References: F. & W. If 18, 23, 307; Van S. pp. 189-199. 











DAIRY HUSBANDRY 


53 


SERIES H 

TESTING BUTTER 

Materials necessary for 10 students: 

10—Yz pint glass top fruit jars (Ball Ideal). 

*10—Farrington Butter fat test bottles. 

10—Aluminum Beakers (125 cc.). 

10 — 4" spatulas. 

5—250 cc. volumetric flasks. 

1—Wisconsin high pressure oven, or 
5—Alcohol lamps, or 

5—Bunsen burners and Benkendorf ovens. 

25cc. —Potassium Chromate (K 2 CrOf) solution (F. & W. f 278). 
200cc.—Silver nitrate (. AgNoz) solution. (F. & W. If 278.) 

1 — Kg. petroleum ether or high test gasoline (for ether extrac¬ 
tion test). 


EXERCISE NO. 39 

Object: To become acquainted with the Farrington test for fat in butter. 

Procedure: The important step in testing butter as well as milk or cream 
is obtaining a correct sample. This is accomplished as follows 
when taken direct from the churn; bring butter up on table, 
wipe free moisture from above doors. Cut the top off butter 
with a ladle and with a spatula obtain a small sample (5-10 
grams each) from at least 5 different places along the full length 
of the butter, and place in the half pint glass top fruit jars. 
Seal the jar. Care should be exercised to avoid having free 
water dropping into the jar. 

If the sample is to be taken from a box, tub, or print, a trier 
should be used to obtain a representative sample. Do not 
shake trier to remove free w r ater. 

A. Warm the butter so that it is in a semi liquid condition, at a 
temperature of about 100° F. Beat with a spatula until it has 
a uniform, creamy consistency. Avoid oiling off. 

B. Weigh a clean, empty, especially constructed Farrington 
butter fat bottle, and record its weight. Pour into the bottle 
enough of the prepared sample to bring to about the 47 gram 
mark, weigh again, and by subtracting the first weight from 
the last, obtain the weight of the butter and record it. 

C. Place thebottle in a hot water bath (160°+F.) for fifteen minutes 
remove to a Babcock centrifuge and whirl at Lop speed in a hot 
tester for fifteen minutes. Place in a hot water bath at 140° 
F. for 10 minutes and read quickly the top and bottom of the 
fat column. Obtain the net weight of the fat by subtracting 
the smaller reading from the larger. 


54 


LABORATORY MANUAL 


D. Calculate the per cent fat as follows: 

Net reading 

- X 100 = % fat. 

grams butter in bottle 

Note: A sharper dividing line may be obtained by dropping 
a small quantity of strong hot salt water through the fat after 
whirling. 


Obser\ations: 


Sample 

Weight of Butter 

Net Reading 

% fat 

1 




2 





Conclusions: 

Questions: (1) Name four other fat tests which may be used for de¬ 
termining the fat content of butter. 

(2) Why is the Babcok test not commonly used for determining 
the fat content of butter? 

(3) How is the silver nitrate solution for the salt test, described in 
exercise 41, prepared? 

(4) How is the indicator for the butter salt test prepared? 

References: F. & W. 102—103d, inclusive, 278, 278a; Van S. pp. 112— 

130; Jud. p. 86. 















DAIRY HUSBANDRY 


55 


EXERCISE NO. 40 

Object: To become acquainted with a factory test for moisture in butter. 

Procedure: Millions of dollars are lost annually by the creamery in¬ 
dustry because of ununiform composition of butter. 

A. Warm the butter so that it becomes soft, but avoid oiling off. 
A temperature of 80°-100° F. will best accomplish this. Beat 
with a spatula until it has a uniform thick custard consistency. 
Weigh out exactly *10 grams into a clean dry aluminum dish 
which has been balanced on the right hand pan of a Torsion 
moisture test scale. When balancing the dish, the 1 and 2 
gram weights should be kept at rest at the extreme left end of 
their respective riders. 

B. Place the dish containing the 10 grams of butter in a Wisconsin 
high pressure oven or hold over an alcohol flame, or place in a 
Benkendorf oven until all foam has disappeared and the butter 
has a brown appearance. Remove the dish and allow to cool 
in a dry place. 

C. Place dish on right hand pan of scale and move the two and 
one gram weights to the right until the scale again balances. 
The per cent moisture is read direct off the riders. 

D. Save the sample for Exercise 40 or 41. 

Note: By using dishes of approximately equal weight and 
the small tare weight, a number of samples may be weighed out 
in succession on the same scale. 

Observations: 


Sample 

Weight 

% Moisture 

1 



2 




Conclusion: 


Questions: (1) What is the legal standard for butter in this state? In 
the United States? 

(2) Give a brief description of each of the following methods of 
evaporating the moisture from butter: Patrick, Irish, Wiscon¬ 
sin high pressure oven, Benkendorf oven. 

(3) If a sample, while being prepared, is warmed to such an extent 
that it oils off, how should it be treated in order that a repre¬ 
sentative 10 grams of butter can be obtained? 

(4) Name several precautions that should be taken during the 
weighing and evaporating process. 


References: F. & W. If 272-277, inclusive; Van S. pp. 112-124. 













56 


LABORATORY MANUAL 


EXERCISE NO. 41 

(42 should be substituted at this point if the ether extraction test is to 

be made.) 

Object: To become acquainted with the salt test of butter. 

Procedure: In the average creamery where one man performs many 
duties, it is customary to make but one or two tests of butter; 
always the moisture and occasionally the salt test. It is as¬ 
sumed that average butter contains 1% of curd, hence the fat 
content of the butter is approximated by difference as follows: 

100—(% moisture + % salt -f 1) = % fat. 

A. If the moisture test has been made or if the ether extraction 
test (Exercise 42) has been made, the residue is used for the 
salt test. If neither has been made the sample is obtained 
and weighed out as for the moisture test. 

B. The fat, curd and salt mixture is transferred to a pint jar or 
bottle with 250 cc. of warm (110° F.) water, measured out in a 
250 cc. volumetric flask. Mix thoroughly with a rotary motion 
and allow a few seconds for the fat to rise. 

C. Transfer 17.6 cc. of the mixture to a white cup. Hold finger 
over upper end of pipette while it is being inserted to prevent 
the entrance of fat. 

D. Add two drops of potassium chromate indicator and titrate 
with the prepared silver nitrate solution. 1 cc. of the solution 
indicates 1% salt. 


Observations: 


Sample 

Weight 

cc. Ag No 3 Solution 

% Salt 

1 




2 





Conclusions: 

Questions: (1) Give the chemical reactions taking place in the salt test. 
Use equations. 

(2) Why should the silver nitrate solution be kept in brown glass 
bottles? 

(3) What is the purpose of adding salt to butter? 

(4) Why does the amount of salt that can be incorporated in butter 
depend upon the moisture content of the butter? 

References: F. & W. ^ 278; Van S. pp. 125-130. 











DAIRY HUSBANDRY 


57 


EXERCISE NO. 42 

Object: To become acquainted with the ether extraction method of fat 
determination of butter. 

Note: High test gasoline may be substituted for ether. 

Procedure: “Attempts have been made to use the Babcock glassware 
and tester for the determination of fat in butter, but the results 
have not been entirely satisfactory, and only a fair degree of 
accuracy may be expected.” (F. & W. 1 102-103.) 

A. Determine the moisture content of a sample of butter as out¬ 
lined in Exercise 40. Use a rather narrow lipped aluminum 
beaker having a capacity of about 100 cc. 

B. After the breaker is weighed to determine the loss in moisture, 
fill with petroleum ether and stir with a glass rod. Cover with 
a watch crystal and allow to stand for 2 or 3 minutes to allow 
the curd and salt to settle. Decant off the solvent without 
disturbing the sediment. Fill with petroleum ether again and 
stir. Allow to settle. Decant off after a short time. 

Best results will be obtained if both the ether or gasoline and 
fat are warm. 

C. Heat the beaker gently over hot plate, or water bath to 
drive off ether. Avoid sputtering due to overheating. 

D. Reweigh the beaker and determine the per cent fat by the dif¬ 
ference in weight. 

E. Determine the salt content of the residue as in Exercise 41. 

Note: The result for the curd will be slightly low and that 
for fat high due to a slight loss (about .2 per cent) in decanting 
off the ether fat mixture. 

Observations: 


Sample 

Weight 

Weight of water 

% water 

Weight of fat 

% fat 

1 






2 







Conclusions: 

Questions: (1) What is the average composition of American butter? 

(2) What is the legal standard for butter in each of the four leading 
foreign butter producing countries? 

(3) Name the five leading butter producing states in the U. S., and 
give the amount each produces. m 

(4) Name the four leading butter producing nations. 

References: F. & W., p. 307; Van S. p. 16. 














58 


LABORATORY MANUAL 


SERIES I. 

Testing Cheese. 

Materials necessary for 10 students: 

5— 5 gram weights. 

5—9 or 10 gram weights. 

5—2 gram weights. 

*10—small tin evaporating dishes. 

1—High pressure oven. 

EXERCISE NO. 43 

Object: To determine the fat content of cheese by using the Babcock test. 

Procedure: “It is important in testing cheese, just as in other dairy prod¬ 
ucts that a correct sample be obtained. This is done as follows: 
Draw a plug from a sound portion of the cheese with a cheese 
trier; this should be taken at a point that is not near the rind, 
a cut surface of the cheese, a defective spot or an old trier hole. 
Cut off the top one-half inch of the trier plug and replace it 
in the trier hole to protect the cheese.” (F. & W. f 105.) 

A. Carefully weigh 9 or 10 grams of cheese into a 30% cream 
test bottle. The more finely divided the cheese when placed 
in the test bottle, the easier it will be to get the cheese into solu¬ 
tion. Add from 10-15 cc. of hot water and allow the cheese to 
emulsify. Hold the bottle in a hot water bath to complete the 
emulsification if necessary. The addition of 2-3 cc. of sulfuric 
acid, and vigorous shaking from time to time will also aid in 
the emulsification. 11 is important, in order that satisfactory 
results be obtained, to have all cheese emulsified. When no 
more lumps are seen in the liquid add 17.5 cc. of sulfuric acid, 
and complete the test in the usual manner. 

B. Whirl in centrifuge as for milk. 

C. Read as for cream, and calculate the test by using the formula: 

Reading X18 

-= % fat. 

grams used 

Note: Add acid in small quantities as a large quantity at one 
time causes too intense action. Carefully wash down all 
cheese particles from the neck of the bottle before adding 
the acid. 

Observations: 


Sample 

Grams cheese 

Reading 

% fat 

Condition 

Color 

1 






2 







Conclusion: 














DAIRY HUSBANDRY 


59 


Questions: (1) What is the legal standard for fat and moisture in 
American or cheddar cheese in this state. 

(2) Which breed, the Holstein or the Jersey on an average give 
the greater yield of cheese per 100 pounds of milk? Prove 
your answer. 

(3) How may the yield of cheese be calculated by means of the 
Babcock test and the lactometer? 

(4) What is the average composition of Holstein milk, Jersey milk, 
Guernsey milk, Ayrshire milk? 

References: F. & W. 104, 105, 224, 307; Van S. pp. 6, 109; Jud. pp. 

86-87; St. p. 316. 


60 


LABORATORY MANUAL 


EXERCISE NO. 44 

Object: To become acquainted with the cheese moisture test. 

Procedure: Of all laws pertaining to the composition of cheese, the one 
regulating the moisture content is most rigidly enforced. 

A. Read carefully the instructions pertaining to testing the mois¬ 
ture content of butter (Series H, Exercise 40, part A). Obtain 
a representative sample of cheese and weigh out 10 grams 
in a tin or aluminum evaporating dish. Place dish in a Wis¬ 
consin high pressure oven and evaporate at a pressure of 30 
pounds for 5 hours. Allow dish to cool and place on right hand 
pan of scale. Place a 2 gram weight on the pan with the dish. 
Slide the 2 gram weight on the beam to the right to a conven¬ 
ient point on the beam and then slide the 1 gram weight to the 
right until the pans balance. The 2 gram weight on the pan 
indicates 20%, and the reading on the beams is readily ob¬ 
tained. Adding the reading on the beams to 20% will give the 
per cent of moisture present. 

B. If a 5 gram sample of cheese is weighed out instead of a 10 gram 
sample, it is unnecessary to use the 2 gram weight on the pan. 
In that case the reading on the beam obviously has to be mul¬ 
tiplied by 2 in order to give the per cent moisture. 

Note: By using a set of weights or dishes of very nearly equal 
weight, a number of samples may be weighed out on the 
same scale in rapid succession by merely keeping a record of 
the position of the small tare weight on the short graduated 
beam. 


Observations: 


Samples 

Grams Sample 

Weight after 
evaporating 

% moisture 

1 




2 





Conclusions: 


Questions: (1) Why is the butter moisture test not adaptable to cheese 
moisture testing? 

(2) How may the approximate yield of cheese be obtained from 
the fat test of milk? 

(3) How may the yield of cheese be obtained from a casein and fat 
test? 

(4) Name four suggested plans of paying for milk at the cheese 
factory and briefly illustrate each. 

References: F. & W. H 223, 224, 225, 242, 243, 244, 245, 285; Van S. pp. 
259-261; St. pp. 317-318. 












DAIRY HUSBANDRY 


61 


SERIES J. 

Ice Cream Testing. 

Materials necessary for 10 students: 

500cc.—Mixture of glacial acetic and concentrated hydrochloric acid, 
equal parts. 

10 — 125cc. glass beakers. 

3—50 cc. Burettes and stands. 

3—250 cc. flasks. 

3—200 cc. flasks. 

*1—Benkendorf 50 cc. sampler. 

3—Glass funnels. 

3—1 cc. pipettes. 

50 cc. — Ether. 

EXERCISE NO. 45 

Object: To test ice cream for fat in the Babcock tester, by means of the sul¬ 
furic acid method. 

Procedure: Great care should be exercised in obtaining a correct sample 
because of the large amount of foam usually present. Pouring 
the melted sample back and forth at least 10 times will usually 
eliminate most of the foam. 

A. "Weigh out 9 grams of the melted ice cream into an 18 gram 
test bottle. Add 9 grams of luke warm water. At intervals of 
a minute or two add small quantities of sulfuric acid (sp. gr. 
1.82-1.83). Shake well after each addition and continue add¬ 
ing until a chocolate brown color appears. Add at once a few 
cc. of cold water to check the action of the acid. 

B. Centrifuge as for milk except that two whirlings and one filling 
are sufficient. 

Note: It may be advisable to check the action of the acid by 
cooling the mixture after each addition of acid by holding 
the test bottle for a short time in cold water. 

Observations: 


Sample 

Gram sample 

cc. acid 

Reading 

% fat 

Condition 

1 






2 

* 






Conclusions: 

Questions: (1) Why is the mixture not allowed to become hot as in test¬ 
ing cream? 

(2) What is the Mojonnier tester for fat and solids, and of what 
established tests is it an adaptation? 

(3) How may milk powder be tested for fat? 

(4) What is the legal standard for ice cream in this state? 
References: F. & W. 107, 108; Van S. pp. 95-100; Jud. pp. 87-88; 

St. p. 543. 














62 


LABORATORY MANUAL 


EXERCISE NO. 46 

Object: To become acquainted with the Glacial Acetic and Hydrochloric Acid 
method for testing ice cream for fat in the Babcock test. 

Procedure: Laws differ in regard to ice cream, but agree in most cases 
on a fat standard. This may vary from as low as 6% as the 
minimum in some states, up to 14% as the minimum in other 
states. 

. A. Weigh into an 18 gram test bottle 9 grams of thoroughly mixed 
ice cream. Add 20 cc. of the mixture of glacial acetic and 
hydrochloric acid as prepared under “materials required.” 
Shake well and place the test bottle in a hot water bath until a 
brown color appears. 

B. Whirl in a Babcock centrifuge as for milk, and read as a cream 
test is read. 


Observations: 


Sample 

cc. sample 

cc. acid 

R ; 11 l' 

% fat 

Condition 

1 






2 







Conclusions: 

Questions: (1) What is the average composition of commercial ice 
cream? 

(2) What is meant by the term milk solids in ice cream? What 
ingredients are used to increase the milk solids? 

(3) What is the average output in gallons of ice cream in the United 
States in one year? In this state? 

(4) What is the per capita consumption of ice cream in the United 
States per year? 

References: F. & W. 108; Van S. pp. 95-100. 














DAIRY HUSBANDRY 


63 


EXERCISE NO. 47 

Object: To become acquainted with the Acetic and Sulfuric acid test for ice 
cream by using Babcock equipment. 

Procedure: For ice cream that contains chocolate and has been homo¬ 
genized at a high pressure, it is very difficult to obtain a repre¬ 
sentative result with any of the methods described in this 
manual. 

A. Weigh out a 9 gram sample of thoroughly mixed ice cream into 
a 30% cream test bottle. Add 9 cc. of water to dilute the 
sample. Add 5 cc. of acetic acid and then add carefully 6-8 cc. 
of sulfuric acid (sp. gr. 1.82-1.83). Centrifuge and read as 
for cream. Multiply the reading by 2 if an 18 gram test 
bottle is used. 

Observations: 


Sample 

cc. sample 

cc. acetic 
acid 

cC. sulfuric 
acid 

% fat 

Condition 

1 






2 







Conclusions: 


Questions: (1) About how many pounds of milk are required to make 
one gallon of ice cream? 

(2) What is the average composition of ice cream? 

(3) If a 7 gram sample of ice cream gave a reading of 4.9 in an 18 
gram bottle, what % fat did the ice cream contain? 

(4) If a 12 gram sample of ice cream gave a reading of 15 in a 9 
gram bottle, what % fat did the ice cream contain? 

References: F. & W. 108; Van S. pp 95-100; Jud. pp 87-88. 



>< • - . ,• 













64 


LABORATORY MANUAL 


EXERCISE NO. 48 

Object: To become aeguainted with the Benkendorf lest for over-run in ice 

1 cream. 

Procedure: There are now on the market a half dozen or more contriv¬ 
ances for determining the over-run of ice cream directly in 
the freezing room .very rapidly, provided the weight of the 
“mix” before freezing is known, or if a sample of “mix” is kept 
on the over-run tester throughout the process. These con¬ 
trivances are not adaptable for inspectors who desire to obtain 
the over-run of an already frozen mix which they know nothing 
about. For such, the Benkendorf test is used. It is based on 
the principal that when ice cream is melted, the volume of the 
ice cream will shrink to the original volume of the “mix.” 

A. Take a 50 cc. ice cream sampler and immerse in the ice cream 
to be sampled. Allow it to remain there a short time to become 
thoroughly chilled. Withdraw the sampler, and with a spatula 
level both ends of the sampler. Transfer the sample to a 250 
cc. flask by means of 200 cc. of hot water. This can be done 
by using a funnel. Shake with a rotary motion until all the 
ice cream is melted. 

B. By means of a burette containing hot water, the mixture can 
be brought up to the 250 cc. mark. To get rid of the foam add 
1 or 2 cc. of ether. Water is again added to bring the mixture 
to exactly the 250 cc. mark. 

C. The number of cc.’s of water added from the burette plus the 
number of cc.’s of ether represents the shrinkage of the 50 cc. 
of ice cream. The calculations for determining the over-run 
are as follows: 

Let A =the water and ether used in step C, and 50 (volume 

of sampler)—A =B. 

A 

— X100 = % over-run. 

B 

Note: In order that no appreciable error be introduced, it is 
recommended that the 250 cc. flask be wetted and drained 
before transferring the ice cream, in order to compensate for 
the water adhering to the 200 cc. flask. 

Observations: 


Sample 

cc. water and 
ether used* 

50—A 

% over-run 

1 




2 





Conclusions: 


Questions: (1) How may over-run in ice cream be calculated by weight? 

(2) What is considered an average over-run in ice cream? 

(3) What is modified milk, and what are its uses? 

(4) What is the average output of malted milk in the United States 
in one year? 












DAIRY HUSBANDRY 


65 


SERIES K. 

Condensed Milk Testing. 
Materials necessary for 10 students: 

5 250 cc. flasks. 


EXERCISE NO. 49 

Object: To determine the fat content of unsweetened condensed milk by 
means of the Babcock test. 

Procedure: Due to the condition of the milk, the sugar that may he pres¬ 
ent, etc., it is very difficult to test condensed milk for fat. 

The following method is, however, suggested for unsweet¬ 
ened condensed milk. 

A. Exercise great care so as to obtain a representative sample 
from the can of milk. Dilute 25 cc. of condensed milk with 
75 cc. of water, making 100 cc. Test as for whole milk, but 
fill the bottle after the first and second whirling with a hot mix¬ 
ture of acid and water 1:1. Read as for milk. 

B. Calculate the per cent fat as follows: 

Reading X18 

-= % fat 

4.4 

Note 1: In order to get a good sample, it may be necessary 
to heat the sample to 130° F. for 10 minutes, and then shake 
well before opening the cans. 

Note 2: If sweetened condensed milk is to be tested the plan 
of Exercises 46 to 47 may be followed. 

Observations: 


Sample 

Reading 

% fat 

Condition 

1 




2 





Conclusions: 

Questions: (1) What is the government standard for condensed and 
evaporated milk? 

(2) How many pounds of whole milk are necessary to manufacture 
one pound of condensed milk? 

(3) Nane the important uses of condensed milk. 

(4) Why is it absolutely necessary to have a good quality sweet 
milk when it is to be condensed? 


References: F. & W. f 264; Van S. pp 95-100; Jud. pp 87-88. 














66 


LABORATORY MANUAL 


EXERCISE NO. 50 

Object: To determine the specific gravity of condensed milk. 

Procedure: By knowing the fat tests and solids not fat of the milk enter¬ 
ing into the manufacture of condensed milk, and then again 
testing the condensed milk for these constituents, it is possible 
to determine the concentration. 

A. Take 50 grams of thoroughly mixed condensed milk, weigh 
into a tared beaker, and wash with enough warm water into a 
flask to make exactly 250 cc. Cool to 60° F. and obtain the 
specific gravity with an accurate lactometer. Designate the 
reading expressed as specific gravity as “a.” 

B. Calculate the density of the condensed milk as follows: 

1 

sp. gr. of condensed milk =-. 

6-5a 

C. The concentration ol the condensed milk, if the specific gravity 
and fat content of the original is known, is determined as fol¬ 
lows: 

as 

Concentration (C) =-. 

aisi 

a—solids not fat of condensed milk. 

s—specific gravity of condensed milk.. 

ai—solids not fat of milk used. 

Si—specific gravity of milk used. 

Observations: 


Sample 

Sp. gravity of dilution 

Sp. gravity of condensed milk. 

1 

/ 


2 




Conclusions: 


Questions: (1) Give the four states leading m the manufacture of con¬ 
densed and evaporated milk. 

(2) What is the difference between condensed and sterilized milk? 

(3) Why is sugar often added to condensed milk during its manu¬ 
facture? 

(4) What is the approximate difference in composition between or¬ 
dinary condensed and sweetened condensed? Give figures. 

References: F. & W. 264, 307. 














DAIRY HUSBANDRY 


67 


SERIES E. 

Quality Tests (Special) 

Materials necessary for 10 students: 

1—Sediment tester and cotton disks. 

. 100 — 5" test tubes. 

100 cc.—Methylene blue solution (1 part crystalline dye in 2000 parts 
water. Redilute just before use so that the concentration is 
1 part dye to 20,000 parts of water). t 

300 cc.—ethyl alcohol solution (60% by weight: 68% by volume). 

1 — Incubator. 

*1—Marschall rennet testing set. 

EXERCISE NO. 51 

Object: To become acquainted with the Wisconsin sediment test for milk. 

Procedure: Aside from a knowledge of the fat content and the acidity 
of the milk, it is highly important that some test be used 
whereby the consumer or manufacturer may establish the care 
that the milk has been given in regard to cleanliness. For this 
purpose the sediment test is widely made use of by city milk 
plants, cheese factories and condenseries. 

A. Place a specially prepared cotton disk on the wire screen of the 
sediment tester and force one pint of the milk to be tested 
through the cotton disk. Paste the disk on one of the cards 
provided and hand in with the exercise. 

Observations: 

Conclusions: 

* 

Questions: (1) Outline how a farmer may produce milk with a good 
sediment test. 

(2) What is the result when dirty milk is used for cheesemaking? 

(3) What is a milk clarifier and how is it used. 

(4) Is a good sediment test always an indication that the milk is 
good? Explain your answer fully. 

References: F. & W. *[ 298; Van S. pp 163-168; St. pp 144-145. 


LABORATORY MANUAL 


08 


EXERCISE NO. 52 

Object: To become acquainted with the Methylene blue reduction test and the 
Fermentation test of milk. 

Procedure: The fermentation test and the Methylene blue test may be 
performed separately as an individual test or they may be com¬ 
bined as one test. The tests are of greatest value to the cheese 
maker to detect abnormal fermentations. They may be used 
^ by the buttermaker as well to locate off-flavors. They are of 
greatest value when combined with the acidity test for then 
they will give a clue to the kind of organisms present. The 
aim of the Methylene blue test is to place the milk into certain 
defined grades which may be tabulated somewhat as below. 
The number of organisms, of course, is relative and is given 
merely as a matter of interest. 


Grade 

White after 

Organisms 

1 

53^ hrs. 

0-500,000 

2 

2-5 V 2 hrs. 

500,000-4,000,000 

3 

H-2 hrs. 

4,000,000-20,000,000 

4 

Less than 3^ hr. 

20,000,000-up ward 


A. Wash and clean five test tubes. Sterilize by placing in a w're 
basket and placing under a pail which has been inverted over 
a steam jet. The steam is then turned on for a period of 15 
minutes. If no steam is available the test tubes may be placed 
in boiling water for 10 minutes. 

B. Use one test tube for each patron. Catch the milk in the test 
tube directly out of the patron’s can while the can is being 
dumped. Add 1 cc. of Methylene blue solution to each test 
tube and mix. Place the test tube in an incubator at 98° F. 
Observe after hourly intervals and record the color ot the milk. 
Compare with the table above. 

C. If the test tubes are left in the incubator for 24 hours and their 
ap pearance noted it will be possible to determine to what class 
of organism the reduction was due. The appearance of the 
milk in the test tubes is also indicative of the quality of cheese 
which it will make. The fermentation test may be made inde¬ 
pendent of the Methylene blue test. 














DAIRY HUSBANDRY 


69 


Observations: 


Sample 

Acidity 

Reduction time 

Fermentation 

Grade 

1 





2 





3 





4 





5 






Conclusions: 

Questions: (1) Give a brief description of the Wisconsin curd test. 

(2) How should milking machines be cleaned in order to produce a 
good grade of milk? 

(3) What is certified milk? 

(4) Describe several types of milk and cream coolers. 

References: F. & W. If 153 to 158, inclusive; Van S. p. 163. 

















70 


LABORATORY MANUAL 


EXERCISE NO. 53 

Object: To become acquainted with the alcohol test for quality of milk. 

Procedure: It has been claimed that the alcohol test is a better indication 
of the suitability of milk for condensing than the acidity test. 

A. The alcohol solution is prepared by using ethyl alcohol, diluted 
with distilled water so that it contains 60% by weight or 68% 
by volume of ethyl (grain) alcohol. 

B. The test is made by using a clean small test tube and tilling 
about one-third of the milk to be tested. An equal quan¬ 
tity of the above alcohol solution is added and mixed. After 
mixing, the tube should be slowly raised to a vertical position. 
White flakes on the glass indicate a strong degree of acidity. 
A slight film indicates a slight degree of acidity. A clear glass 
indicates a low degree of acidity. 

C. Test the milk provided by means of Mann’s acidity test and 
compare with tests of the same milk made with the alcohol 
solution. 


Observations: 


Sample 

% Acidity 

Condition with alcohol test 

1 



2 



3 




Conclusions: 

Questions: (1) How much light and ventilation should be provided for 
each cow when a stable is being constructed? 

(2) How should a milk house be constructed and where should it 
be located? 

(3) Why are partly covered pails superior to the open top pail? 

(4) Why should turnips, ruta-bagas, silage, etc., not be fed during 
the milking period? 

References: F. & W. ^ 152-158; Van S. pp. 153-154. 











DAIRY HUSBANDRY 


71 


EXERCISE NO. 54 

Object: To become acquainted with the Marschall rennet test. 

Procedure: The rennet test is used by cheesemakers to determine the 
ripeness of the milk. It is claimed that rennet tests are more 
sensitive to acidity during the early phases of acid develop¬ 
ment than the acid tests, and hence are to be preferred by 
cheese makers. 

A. Fill the small glass with pure water to the mark and pour into 
it 1 cc. of rennet extract. Rinse the pipette with the same 
water. 

B. Fill the cup with milk to the zero mark, add rennet, mix 
thoroughly and allow to stand. 

C. Milk will flow from the cup until coagulated. The scale on 
the inside of the cup shows directly the time necessary for coag¬ 
ulation. The sweeter the milk, the more will flow from the 
cup. 

Note: For cheese making the correct degree of acidity is 
from 0.19-0.21%, or when the milk coagulates at 2^ spaces 
Marschall rennet test, and rennet should be added at that 
time. 

Observations: 

Conclusions: 

Questions: (1) Describe the Monrad rennet test. 

(2) What is rennet extract, and how is it obtained? 

(3) Why is it important that milk develop the proper degree of 
acid when making cheese? 

(4) What is the object of adding rennet extract to milk when 
making cheese? 

References: F. & W. 157, 158; Jud. pp. 238-241; St. pp. 304-306. 


PART II—MANUFACTURE OF DAIRY 
PRODUCTS 

SERIES A. 

Butter. 

Materials necessary for 10 students: 

1—Hand, or small power churn. 

Sufficient cream to fill churn one-third full. 

1—Acidity testing outfit. 

4 — Pails. 

2—20 gallon cans. 

50cc.—Butler color. 

10—Pounds butler salt. 

Sufficient cold water (under 58 F..) 

2 — Ladles. 

Several tubs fully lined. 

1—Worker if hand churn is used. 

EXERCISE NO. I 

Object: To become acquainted with the manufacture of Dairy Butter. 

Procedure: Buttermaking is a science and to make good butter is an art. 

Without study and practice, no one can make good butter, but 
above all things the greatest asset is the best kind of cream. 

A. Careful observation and adherence to the following points will 
aid immensely in producing high grade butter. 

(1) Milk utensils and separator should be thoroughly washed 
and scalded after use. Sunlight is the best drying agent 
and an excellent disinfectant. 

(2) Set the separator so that it skims a cream testing 30-35% 
fat. 

(3) Cool cream rapidly after skimming to 50° F. or below. 

(4) Do not mix fresh cream with cream from a previous skim¬ 
ming until both have the same temperature. 

(5) Aim to have the cream of the same acidity at every churn¬ 
ing in order to produce butter of a uniform quality. On 

the farm, temperature is the controlling agency. Imme¬ 
diate cooling to a low temperature will result in low acidity. 
Warming cream to 65 -75° F. and holding at that tempera¬ 
ture will tend to increase the acidity. Do not guess. Test. 

(6) Hold the cream at churning temperature or below for at 

least two hours before churning. 

(7) Wash the churn, ladles, butter worker, and all churning 
utensils; scald with hot water, and finally cool with plenty 
of cold water to a temperature below the churning tem¬ 
perature. 

(8) Strain the cream into the churn. See that the churn is not 
over one-half full. 


I 


DAIRY HUSBANDRY 73 

(■*) Aclcl enough butter color to give the butter the same shade 
of yellow that it has in the summer months. (The amount 
of color varies from 10-40 cc. per 100 pounds of fat.) 

(10) Revolve the churn at such a speed that the cream pounds 
hard against the sides of the churn (30-50 R. P. M.), open 
vent plug several times during the first 50 or 75 revolutions 
to allow gas to escape. Stop churning when the granules are 
the size of cracked corn. 

(11) Drain out the buttermilk using a strainer to catch any par¬ 
ticles of butter. 

(12) Wash the butter with about the same amount of water as 
there was cream in the churn and at a temperature a few 
degrees below that of the buttermilk. Revolve the churn 
5 or 6 revolutions. Drain out wash water, and repeat if 
necessary. 

(13) If a hand churn is used remove the granular butter to the 
rinsed worker and distribute the salt evenly at the rate of 
^—1 oz. per pound of butter fat. In the power churn a trench 
is made and the dampened salt is distributed evenly in the 
trench. 

(14) Work the butter until it is waxy and no longer gritty. 

(15) Pack the butter in suitable containers. 

(16) Clean the churn and utensils. 

Observations: 

Weight of cream . 

Test of cream . 

Pounds butter fat in cream.. 

Pounds butter made . 

( Butter-fat \ 

-X100 ) . 

Fat / 

Acidity of cream . 

Temperature of cream . 

Time to churn.. 

Size of granules . 

Temperature of buttermilk . 

Temperature of wash water . 

Amount of salt. 

Rate of salt . 

Pounds of buttermilk. 

Test of buttermilk. 

Conclusions: 

Questions: (1) Give 5 reasons for difficult churning on the farm. 

(2) What is the effect on the butter if cream is churned too worm, 
or if the wash water is too warm? 

(3) W ; hat is meant by the term “ripening” and why is cream 
ripened? 

(4) W hat advantages has creamery butter making over farm butter 
making? 

References: Jud. pp. 193—215; St. pp. 235—288, 396—418. 























74 


LABORATORY MANUAL 


EXERCISE NO. 2 

Object: To determine the influence of temperature of cream on the time oj 
churning, the test of the buttermilk, and the quality of the butter. 

Procedure: The temperature of the cream is one of the most important 
factors determining the ease with which the cream churns. * 
Any conditions which tend to make churning difficult call for 
an increase in the churning temperature. Any conditions, on 
the other hand, which tend to hasten the churning process, call 
for a decrease in the churning temperature. Generally the 
range for churning temperature is between 48°-60° F. 

A. Divide a lot of cream into two equal parts. Hold one lot at a 
temperature of 60° F. for 2 hours, and the other lot at 50° 
or 52° F. for 2 hours. 

B. Churn each lot of cream under the same conditions following 
the method outlined for Exercise 1. 

C. Record the time of churning for each lot, make a test of the 
butter milk, and set aside a print of butter of each lot for har¬ 
dening and scoring. 

Observations: 


Sample 

Churning temperature 

Time of 
Churning 

Test of 
Buttermilk 

Quality of 
Butter 

1 





2 






Conclusions: 


Questions: (1) In addition to the effect on the buttermilk test, the body 
and time of churning, give three other effects of high or low 
churning temperature. 

(2) Name four factors aside from temperature that effect the hard¬ 
ness of fat. 

(3) Why should cream be strained into the churn? 

(4) Why is color added to cream? What is the nature of butter 
color? 

References: Jud. pp 193-215; St. pp 235-288, 396-418. 













DAIRY HUSBANDRY 


75 


EXERCISE NO. 3 

Object: To determine the effect of acidity on the time required to churn, on 
the test of the buttermilk and on the quality of the butter. 

Procedure: Sweet cream is viscous or sticky, but the acid in cream seems 
to reduce the viscosity although the cream becomes thicker. 

A. Divide a lot of sweet cream into two equal parts. Keep one 
part sweet by holding it at a low temperature. Ripen the other 
part at 70°-75° F. until it contains approximately .20% more 
acid than the sweet cream—then cool to the same temperature 
as the sweet cream and hold at that temperature lor 2 hours. 

B. Churn both lots of cream under the same conditions and tem¬ 
perature. 

C. Record the length of time required to churn, and the test of the 
buttermilk. Set aside a print of butter from each lot for deter¬ 
mining the quality of the butter. 

Observations: 


Sample 

Acidity 

Churning 

Temperature 

Time of 
Churning 

Test of 
Buttermilk 

Quality of 
the butter 

1 




• 


2 







Conclusions: 

Questions: (1) What is meant by pasteurization, and what are the ob¬ 
jects of pasteurizing cream for buttermaking? 

(2) What are the causes of mottles in butter? 

(3) What are the causes of a greasy body in butter? 

(4) What is the cause of a leaky body in butter? 

References: Jud. pp 193-215; St. pp 235-288, 396-418. 













76 


LABORATORY MANUAL 


SERIES B. 

Cheese 

Materials necessary for 10 students: 

6 — 12-quart dairy pails. 

1—400 pound val. 

500 cc.—-Rennet extract. 

1—Acidity testing outf’t. 

5 lbs.—Cheese salt. 

1—Curd mill. 

3-—Cheese hoops. 

EXERCISE NO. 4 

Object: To become acquainted with the making of cottage cheese. 

Procedure: There are several ways of classifying the 3-400 kinds of cheese 
made in the world, namely: 

(1) Rennet. 

(a) American. 

(b) Swiss. 

(c) Brick. 

(d) Limburger, etc. 

(2) Non-Rennet. 

(a) Cottage. 

(b) Neufchatel. 

(c) Hand cheese 

(d) Sap-sago, etc. 

A. second classification. 

(1) Ripened. 

(a) Mold ripened. 

(1) Roqueford (France). 

Camembert (France). 

(3) Brie (France). 

(4) Gorgonzola (Italy). 

(5) Stilton (England). 

(b) Bacteria ripened. 

(1) American. 

(2) Swiss. 

(3) Brick. 

(4) Edam (Belgium). 

(5) Gouda (Holland). 

(2) Unripened. 

(a) Cottage. 

(b) Neufchatel. 

(c) Cream. 

A. Twenty pounds of skimmilk are weighed into a clean pail. 
About 20% of lactic starter (sour milk) is added, and the mix¬ 
ture heated to about 95°-105° F. and left in a warm place to 
sour and thicken. The time required for thickening varies in 
accordance with the quantity of starter added or the tempera¬ 
ture held at. 


DAIRY HUSBANDRY 


It 

B. When thick, the sour milk is stirred gently with a thermometer 
or other fine instrument to break the curd up into large lumps, 
not into fine grains or smooth pulp. While stirring, apply heat 
by setting the material on the stove or in hot water until the 
temperature reaches 110°-120° F. 

C. Stop heating and stir occasionally for a period of one-half hour 
or more. This will result in shrinking of the curd. When it has 
shrunk so that it will settle down about two-thirds or three- 
fourths of the way to the bottom under the whey, the whey 
should be removed. 

D. Pour the whey and curd from the pail into a cheese cloth bag 
and allow to drain. As long as the curd remains warm it be¬ 
comes drier and firmer. If there is danger of becoming too dry, 
cold water may be poured over the curd and the cloth then 
hung up to drain. 

E. When drained properly. 1-2% salt is weighed out and mixed 
with the curd. About 13-20 pounds of cottage cheese per 100 
pounds of skimmilk are obtained. 

Observations: 

Pounds milk.. 

Acidity . 

% starter added . 

Temperature at which set . 

Time before thickened . 

Heating temperature . 

Time held hot . 

Pounds cheese . 

% salt . 

Conclusions: 

Questions: (1) What are the causes of acid flavors in cottage cheese and 
what are the remedies? 

(2) W 7 hat are the causes of dry and mealy textures and what arc 
the remedies? 

(3) What are the causes of lumpy textures and what are the 
remedies? 

(4) Describe in what respects the process would differ, if cottage 
cheese were made in larger quantities? 

References: .Jud. pp. 236-249; St. pp. 289-390, 419-451. 



































78 


LABORATORY MANUAL 


EXERCISE NO. 5 

Object: To become acquainted with the process of manufacturing American 
cheese. 

Procedure: In Wisconsin there are four distinct types of cheese made 
The American (often called cheddar, or full cream), Swiss, 
Brick, and Limburger. The American cheese is made from 
partially ripened milk and is usually “set” at a temperature of 
about 86° F. and about 3-3J4 oz. of rennet is used per 1000 
pounds of milk. The Swiss and Limburger cheese require per¬ 
fectly sweet milk and therefore a higher setting temperature 
(about 94° F.) and more rennet (about 4 oz. per 1000pounds) 
is necessary. In American cheese the milk is heated to 102° 
F. or thereabouts to get it dry and firm. Limburger is heated 
to 96° F. to leave it moist. Brick cheese is somewhat inter¬ 
mediate and is heated to about 110°-112° F. to get it dry. In 
order to get the proper texture and “eyes” in Swiss cheese, the 
milk is heated from 128°-136° F. to get the curd dry. 

Brick, Limburger, and Swiss cheese are salted from the out¬ 
side, while the salt is mixed with the curd for American cheese. 
Brick or Limburger cheese is ready to eat in four to six weeks. 
Swiss in four to six months, and American cheese in one to six 
months. 

A. Place 200 pounds of good sweet milk in a cheese vat provided 
with a jacket for heating or cooling, then proceed as follows: 

(1) Heat the milk to 86° F. and make an acidity test. If the 
acidity is less than .19% it may be increased by holding 
at 86° F. for some time or by the addition of good starter 

(sour milk). 

(2) Add color at the rate of Yt-3 oz. per 1000 pounds milk. 
Dilute color with water before adding to milk. Mix milk 
and color thoroughly. 

(3) Add rennet when milk has the proper degree of acidity. 
The amount varies from 2)^-4 oz. per 1000 pounds of milk 
depending on acidity, temperature and composition of 
milk or strength of rennet. Dilute rennet with water 
(40 parts water to 1 pare rennet) before adding. Mix thor- 
ly. 

(4) When the curd is sufficiently firm, it should be cut into 
^-3^inch cubes as follows: lengthwise with a horizontal 
knife, crosswise with a perpendicular wire knife and 
lengthwise with a perpendicular knife. 

(5) Heat the curd to express the whey to about 100° F. The 
acidity of the whey should be .16-18%. 

(6) Draw off the whey and gather the curd in a shallow layer 
on either side of the vat 

(7) Cut curd into blocks 6-8" wide when sufficiently firm. 
Turn the blocks over frequently to prevent cooling off too 
rapidly on one side. 

(8) Mill the curd when of proper texture. 


DAIRY HUSBANDRY 


79 


(9) Salt the curd at the rate of 1^-23^ pounds to each 1000 
pounds of milk. 

(10) Place curd in hoops and press. 

Note: The above are given only as a guide and not as de¬ 
tailed instruction. 

Observations: Give the time necessary for each step, and give results ol 
various tests made. 

Conclusions: 

Questions: (1) Give the approximate production of cheese by the four 
leading cheese states of the United States. 

(2) What is the average composition of American cheese? 

(3) Name the kinds of American cheese which are commonly found 
on the market and give their approximate weight. 

(4) Why is cheese paraffined a few days after removing from the 
press? 


References: Jud. pp. 236-249; St. pp. 289-390, 419-451. 


80 


LABORATORY MANUAL 


SERIES C. 

Ice Cream. 

Materials necessary for 10 students: 

l—1 gallon ice cream freezer (hand power). Materials to make 
y 2 gallon “mix” in the proportion of any of the “mixes” 
given in the exercise. 

75 lbs. — Ice. 

15 lbs.—Coarse salt. 

1 — Thermometer. 

1 — Pail. 

1—Large spoon. 

Hot water. 

EXERCISE NO. 6 

Object: To become acquainted with the manufacture of ice cream. 
Procedure: To make ice cream commercially involves expensive equip¬ 
ment and considerable knowledge regarding the proper prep¬ 
aration of “mixes.” This exercise will take up the preparation 
of ice cream for the home, but under observations, data applica¬ 
ble to the commercial manufacture of ice cream will be called 
for. 

A. Ice cream may be defined as a frozen product made from cream, 
sugar, with or without flavoring and filler. A common classi¬ 
fication of ice cream is as follows: 

(1) Plain ice cream. 

(2) French ice cream or pudding (contains eggs and is usually 
cooked before freezing). 

(3) Fruit and nut ice cream. (Plain ice cream with fruit or 
nuts added after freezing). 

(4) Bisque ice cream. (Plain ice cream with ground up cookies 
or cake). 

(5) Mousse. (W hipped cream heavily flavored with candied 
fruits and nuts and hardened in a packer). 

(6) Sherberts or water ices. 

B. Some basic recipes for approximately 2^ gallons of frozen ice 
cream. 

Plain ice cream: 

l^gsl. 18% cream. 

2 pounds sugar. 

1 oz. vanilla extract. 

2 oz. gelatine or y 2 oz. ice cream powder. 

Formula for French ice cream: 

1 1 / 2 gal. 18% cream. 

2 pounds sugar. 

6 eggs (whites and yokes beaten separately). 

1 oz. vanilla. 

All may be cooked and cooled before freezing. 

C. Freezing the ice cream. 

(1) Cool mixture to below 40° F. The freezer may be turned 
slowly at first to cool the mix. 


DAIRY HUSBANDRY 


81 


(2) Use finely crushed ice and coarse salt (5:1). 

(3) When the mix is well chilled, turn the freezer as rapidly 
as possible to whip in air and to obtain a smooth consis¬ 
tency. When the ice cream has the consistency of thick 
gravy, the dasher should be removed, fresh salt and ice 
packed around and over the can, and set aside to harden. 
In two hours it will be ready to serve. 


Observations: Composition of mix. 


Materia] 

s used 

Fat 

Total solids 

Kind 

Weight 



























Totals 





Method of preparing the mix: 

Pasteurizing temperature .Time. 

Homogenizing temperature.Pressure. 

Emulsifying temperature . 

Aging: 

Temperature.Time. 

Freezing: 

Temperature of mix . 

Temperature of brine . 

Time to freeze.. 

Over-run. 


Conclusions: 

Questions: Define what is meant by the terms “body” and “texture” 
of ice cream. How may each of these be obtained? 

(2) What is the purpose of producing sw r ell or over-run in ice cream? 
What factors affect the over-run? 

(3) Why is the speed of the ice cream freezer important? 

(4) Name 8 dairy products that are used in commercial ice cream 
mixes. 


References: Jud. pp. 216-235; St. pp. 511-546. 






































82 


LABORATORY MANUAL 


SERIES D. 

Hand Separators. 

Materials necessary for 10 students: 

2 —Hand separators. 

6 — Pails. 

60-80—Pounds of milk for each of last 5 exercises. 

EXERCISE NO. 7 

Object: To become acquainted with the principle and construction of a cream 
separator. 

Procedure: The principle upon which the centrifugal cream separator is 
based is the fact that the fat of milk has a specific gravity of 
approximately .90 and is found in the serum (sp. gr. 1.04) as 
an emulsion. As centrifugal force is applied to the milk in a 
separator bowl, the milk is divided into three parts: namely, 
the heavier part, composed of the heaviest portions of the 
milk, albuminoids, ash, sediment, germs, etc., and is commonly 
known as “slime;” the second layer, or next heaviest part is 
the skimmilk, and likewise makes its way to the outside of 
the bowl as a result of centrifugal force. The lightest part 
or cream is crowded to the center of the bowl by the heavier 
skim milk. There is no clear line of demarcation between the 
skimmilk and cream, since separation is continually taking 
place, but the richest cream is always found nearest the center 
of the bowl. The skimmilk nearest the outside of the bowl 
contains the least fat and therefore the separator bowls are 
so constructed that the skimmilk is carried off from the out¬ 
side layer. 

A. Become familiar with each of the separators provided, by as¬ 
sembling, operating, handling, etc. Free use should be made 
of the instruction books. 


DAIRY HUSBANDRY 


83 


Observations: 



1 

2 

3 

4 

5 

Name of separator 






Size by number 


■ 




Capacity 






Height 






Appearance 






Driving mechanism 






Gears 






Oiling system 






Washable parts 






Bowl type 






Bowl—number of parts 






Time to wash 






Ease of washing 






Adjustments 






Speed 






Ease of assembling 






Ease of replacement of worn parts 







Conclusions: 

Questions; (1) Make a detailed sketch of a separate bowl, using arrows 
and different colored inks to indicate the flow and separation 
of the milk. 

(2) Outline briefly the early history of the centrifugal cream sepa¬ 
rator. 

(3) Name the three methods of gravity separation of cream from 
milk. Give figures to indicate the completeness of separation. 

(4) What are the advantages of centrifugal separation of cream 
from milk over the gravity methods? 

References: Jud. pp. 180—192; St. pp. 224—236. 










































84 


LABORATORY MANUAL 


EXERCISE NO. 8 

Object: To determine the capacity and efficiency of a centrifugal cream 
separator. 

Procedure: A cream separator is a delicate machine and should be given 
careful attention. The machine should be well oiled, better 
too much than not enough. A separator, damaged because of 
lack of oil, will never run the same again. The proper grade of 
oil should be selected. The bowl of a separator is its most im¬ 
portant part and should be treated as such. Immersing in 
boiling water or steaming after washing, and then placing out 
to dry will prevent rust. The bowl should not be rinsed before 
washing with scalding water since this tends to bake the albu¬ 
minoids on the bowl parts. The separator should be washed 
after every skimming. If the separator is not to be used for 
any length of time, all of the washable parts should be oiled to 
prevent rust. 

A. Every student should be assigned to a specific duty. Since 
there are 5 skimming exercises, the assignment allowing 5 to a 
separator may be as follows: 

(1) Foreman: Supervision of performance of experiment, as¬ 
sembling and operation of the separator. 

(2) Operator: Assembles bowl; oils machine; operates the ma¬ 
chine; dissembles machine, washes pails and utensils. 

(3) Assistant operator: Flushes the bowl, times the operation, 
pours in the milk; washes the machine. 

(4) Floor man: Obtains, weighs, and warms the milk; cleans 
floor; takes samples to tester. 

(5) Tester: Makes all tests necessary for the experiment. 

B. (1) Warm 20 pounds of milk to 90° F. 

(2) Assemble machine properly and operate at correct speed. 

(3) Flush bowl with one quart of luke warm water. 

(4) Turn on milk and take the time of skimming. 

(5) Flush the bowl at the end of the run. 

(6) Weigh the skimmilk and cream. 

(7) Test the skimmilk and cream. 


DAIRY HUSBANDRY 


85 


Observations: Machine .No.Capacity. 

1. Weight of milk . .. . 

2. Test of milk . 

3. Pounds of fat . 

4. Pounds of cream . 

5. Test of cream . 

6. Pounds of fat in cream . 

7. Pounds of skimmilk . 

8. Test of skimmilk . 

9. Pounds of fat in skimmilk . 

10. Fat unaccounted for 3—(6+9) . 

4X100 

11. Per cent cream is of milk. . 

1 

12. Length of test in minutes. 

(4+7) X60 

13. Capacity.. 

12 

14. Speed of bowl . 

15. Temperature of milk . 

Conclusions: 

Questions: (1) Give four advantages to the patron for skimming a rich 
cream. 

(2) Give six advantages to the butter maker if the patrons deliver 
a rich cream. 

(3) Why should the parts of a separator bowl not be assembled 
until ready for use? 

(4) Give at least three reasons why it is a good idea to flush the 
separator bowl before starting to skim. 

References: Jud. pp. 180—192; St. pp. 224—236. 

























86 


LABORATORY MANUAL 


EXERCISE NO. 9 

Object: To determine the effect of the temperature of the milk on the efficiency 
of separation, and on the amounts of cream and skimmilk, and 
the test. 

Procedure: In purchasing a separator, the following points should be 
considered: 

(1) Number of cows. 

(2) Capacity of the separator. 

(3) Efficiency of skimming. 

(4) Simplicity or ease of cleaning. 

(5) Durability. 

(6) Convenience of obtaining repairs. 

(7) Power to operate. 

(8) Ability of skimming a rich cream without high fat losses. 

(9) Price. 

(10) Ease of oiling—amount of oil needed. 

(11) General construction to promote cleanliness. 

A. Obtain 30 or 40 pounds of milk and divide it into equal parts. 
Skim one part at a temperature of 90° F., flush bowl, and skim 
the second part at a temperature of about 60° F. Follow the 
instruction of Exercise 8 for skimming. 

Note: The class should be shifted so that every member has 
a new position. 

Observations: Machine.No.Capacity. 

(1) Weight of milk . 

(2) Test of milk . 

(3) Pounds of fat . 

(4) Pounds of cream. 

(5) Test of cream .. 

(6) Pounds of fat in cream . 

(7) Pounds of skimmilk . 

(8) Test of skimmilk .. 

(9) Pounds of fat in skimmilk . 

(10) Fat unaccounted for .. 

(11) Per cent cream is of milk . 

(12) Length of test in minutes . 

(13) Capacity . . 

(14) Speed of bowl . 

(15) Temperature of milk . 

Conclusions: 

Questions: (1) How should a separator be washed in order to assure a 
good quality of cream? 

(2) What is the effect on the strain of a separator bowl if the speed 
is doubled? If the diameter is doubled? 

(3) How should cream be cooled in order to insure a good quality? 

(4) Describe the construction of a typical cream cooling tank. 
References: Jud. pp 180-192; St. pp 224-236. 




























DAIRY HUSBANDRY 


87 


EXERCISE NO. 10 

Object: To determine the effect of speed of the bowl on the efficiency of sepa¬ 
ration and the relative quantity of cream and skimmilk, and the 
test. 

Procedure: The composition of the separator “slime” according to 


Fleischmann is as follows: 

Water. 67.3% 

Fat. 1.1% 

Gaseous matter. 25.9% 

Other organic substances. 2.1% 

Ash. 3.6% 


100 . 0 % 

Even with considerable flushing it is almost impossible to re¬ 
move all of the cream from the bowl, hence there is always a 
loss in this respect which is proportionally large in the small 
skimmings. This is important in the selection of a separator. 
A. Obtain 30 or 40 pounds of milk arid divide it into two equal 
parts. Skim one part at a temperature of 90° F. with the bowl 
running at normal speed. Skim the second part at a tempera¬ 
ture of 90° F. with the bowl running at two-thirds of the normal 
speed. Follow instructions given in Exercise 8 for proper 
skimming. 

Note: Shift the class so that every member has a new 
position. 

Observations: Machine.No.Capacity. 

(1) Weight of milk . 

(2) Test of milk . 

(3) Pounds of fat . 

(4) Pounds of cream . 

(5) Test of cream . 

(6) Pounds of fat in cream . 

(7) Pounds of skimmilk . 

(8) Test of skimmilk . 

(9) Pounds of fat in skimmilk . 

(10) Fat unaccounted for . 

(11) Per cent cream is of milk . 

(12) Length of test in minutes . 

(13) Capacity. 

(14) Speed of bowl . 

(15) Temperature of milk . 

Conclusions: 

Questions: (1) Explain the principle of the cream screw. 

(2) Why does the skimmilk screw operate in the opposite direction 
from the cream screw? 

(3) What effect has the amount of flush water used on the test of 
the cream? 

(4) What is the purpose of interior devices in the bowl, e. g., discs? 
References: Jud. pp 180-192; St. pp 224-236. 




































88 


LABORATORY MANUAL 


EXERCISE NO. 11 

Object: To determine the effect of the richness of the milk on the efficiency 
of separation, on the relative quantity of cream and skimmilk, 
and the test. 

Procedure: Steadiness in running is one of the most important factors in 
efficiency of separation. Not only is there incomplete sepa¬ 
ration when a bowl vibrates, but there is danger in operating 
such a machine, since the bowl is likely to jump out and burst. 
The cause of a vibrating bowl may be a bent spindle, machine 
not level, changing covers of bowl, unbalanced bowl, unclean 
bowl, worn out bearings, dented bowl, machine not fastened 
down properly, excessive speed, bearings too tight, poor oil, 
or gummed bearing. 

A. Obtain 20 pounds of milk testing approximately 3%, and 20 
pounds of milk testing approximately 4 or 5%. Skim each lot 
separately at a temperature of 90° F. with the separator at 
normal speed. Follow instructions given in Exercise 8. 

Note: Students are to be shifted so that each one is in a new 
position. 

Observations: Machine.No.Capacity. 

(1) Weight of milk . 

(2) Test of milk . 

(3) Pounds of fat . 

(4) Pounds of cream . . . 

(5) Test of cream. 

(6) Pounds of fat in cream . 

(7) Pounds of skimmilk . 

(8) Test of skimmilk .,. 

(9) Pounds of fat in skimmilk .. 

(10) Fat unaccounted for . 

(11) Per cent cream is of milk .. 

(12) Length of test in minutes . . . . . 

(13) Capacity . 

(14) Speed of bowl. 

(15) Temperature of milk. 

Conclusions: 

Questions: (1) If we assume a loss of .04% of fat in the skimmilk and 
250 pounds of cream are obtained from 2200 pounds of 3.5% 
milk, what is the test of the cream? 

(2) W hat is the loss in butter fat if the test of 2520 pounds of 
skimmilk is .17%? 

(3) How many pounds of cream are obtained from 2820 pounds of 
milk testing 3.6% fat if 85% of the whole milk is skimmilk 
testing .03 %? What is the test of the cream? 

(4) Assuming that there are no losses in the skimmilk, how many 
pounds of 35% cream can be obtained from 450 pounds of 
3.2% milk? 

References: Jud. pp. 180-192; St. pp. 224-236. 

























DAIRY HUSBANDRY 


89 


EXERCISE NO. 12 

Object: To determine the effect of the rate of inflow into the bowl on the effi¬ 
ciency of separation, the relative amount of cream and skimmilk 
and on the test. 

Procedure: Some objections to farm separation of cream are made be¬ 
cause the quality of farm skimmed cream suffers due to im¬ 
proper location of separator, infrequent washing, improper 
cooling of cream, and infrequent deliveries, and because of the 
extra time and power required to operate the separator. 

A. Obtain 30 or 40 pounds of milk and divide into two equal parts. 
Skim part one at a temperature of 90° F. with the separator 
running at normal speed, and the supply valve wide open. 
Skim the second part at 90° F. with the separator running at 
normal speed but with the supply valve only half open. 

Follow the directions given in Exercise 8. 

Note: Shift the class so that each member fills a new position. 

Observations: Machine.No.Capacity.. 

(1) Weight of milk . 

(2) Test of milk . 

(3) Pounds of fat . 

(4) Pounds of cream . 

(5) Test of cream. 

(6) Pounds of fat in cream . 

(7) Pounds of skimmilk . 

(8) Test of skimmilk . 

(9) Pounds of fat in skimmilk . 

(1) Fat unaccounted for . 

(11) Per cent cream is of milk . 

(12) Length of test in minutes . 

(13) Capacity . 

(14) Speed of bowl .... . 

(15) Temperature of milk. 

Conclusions: 

Questions: (1) What are the advantages of centrifugal separation to the 
farmer? 

(2) Give reasons for inefficient skimming of a separator. 

(3) Where should a farm separator be located? 

(4) How is the approximate length of time that the milk remains 
in the separator bowl calculated? 

References: Jud. pp. 180-192; St. pp. 224—236. 

























APPENDIX 


Set of questions illustrating use of the tables in the appendix of 
Farrington & Woll. 

1. How many pounds of fat are there in 17,839 pounds of milk testing 
3.65%? In 4,327 pounds of milk testing 4.35%? (Table VIII.) 

2. How many pounds of fat are there in 1,378 pounds of cream testing 
29%? In 3,967 pounds of cream testing 47%? (Table VIII.) 

3. If butter fat is worth 24^ cents per pound, what would 1,700 pounds 
be worth? (Table IX.) 

4. If butter fat is worth 47c per pound, what would 900 pounds be 
worth? (Table IX.) Show method. 

5. If butter fat is worth 21 \ cents per pound, what would 729 pounds be 
worth? (Table IX.) Show method. 

6. If butter fat is worth 35 cents per pound, what would 387 pounds be 
worth? (Table IX.) Show method. 

7. How many pounds of butter may be expected from 19,837 pounds of 
milk testing 3.9 %? From 43,756 pounds of milk testing 4.7 %? 
(Table XI.) 

8. If the per cent over-run is 19, how many pounds of butter may be 
obtained from 100 pounds of 4.7% milk? From 100 pounds of 3.9% 
milk? (Table XII.) 

9. If the fat content of 100 pounds of milk is 3.9% and the lactometer 
reading is 33, what may be the yield of cheese? (Table XIII.) 

10. How many pounds of cheese may be expected from 9,800 pounds of 
milk testing 3.7% fat and having a lactometer reading of 31? (Table 
XIII.) 

11. How much do 15 gallons of 37% cream weigh? If a container would 
hold 97 pounds of water, how many pounds of 48% cream would it 
hold? (Table XVI.) 

12. If a lactometer gave a reading of 31 at 57° F. what would be the cor¬ 
rect reading? If the reading were 29 at 69° F. what would be the cor¬ 
rect reading? (Table V.) 

13. If a sample of milk testing 3.4% fat gave a lactometer reading of 31, 
what per cent solids not fat would it contain? If the test had been 5.5 % 
and the lactometer reading 33, what per cent solids not fat would it 
contain? (Table VI.) 

14. If the reading on the New York Board of Health Lactometer were 
108, what would this equal on the Quevene? What would 29 equal on 
the N. Y. Board of Health? (Table III.) 

15. What is the legal standard for cream in Oregon? In North Dakota? 
(Table II.) 

16. What is the difference in composition between salted and unsalted 
butter? (Table I.) 


DAIRY HUSBANDRY 


91 


TABLE I 

Production of milk, and rank together with population and number of Dairy Cows 1 . 


State 

Population 

Milk Prod. 
Gals., 000 
Omitted 

Rank 

No. of 
Dairy 
Cows 

Pounds 
Production 
Per Cow 

Ala. 

2348174 

93904 

26 

394112 

1944 

Ariz. 

334162 

14371 

44 

31619 

3724 

Ark. 

1752204 

87624 

29 

415507 

1634 

Cal. 

3426861 

276424 

9 

502415 

4610 

Col. 

939629 

79493 

30 

192234 

2993 

Conn. 

1380631 

54894 

36 

112622 

4128 

Del. 

223003 

11356 

47 

33026 

2924 

Dist. ot Col. 

437571 

512 

49 

704 

6218 

Fla. 

968470 

12156 

22 

71641 

1307 

Ga. 

2895832 

101616 

24 

388448 

2124 

Ida. 

431866 

52365 

38 

115336 

3560 

Ill. 

6485280 

370487 

7 

957313 

3044 

Ind. 

2930390 

238794 

10 

608211 

3044 

Ia. 

2404021 

361426 

8 

897668 

2709 

Kan. 

1769257 

221454 

12 

574257 

3311 

Ky. 

2416630 

146561 

15 

441346 

2666 

La. 

1798509 

32973 

41 

176936 

1324 

Me. 

768014 

77676 

31 

175425 

3724 

Md. 

1449661 

58754 

35 

161972 

3036 

Mass. 

3852356 

76316 

32 

147331 

4352 

Mich. 

3668412 

382823 

6 

802095 

3965 

Minn. 

2387125 

475507 

3 

1229179 

3044 

Miss. 

1790618 

88192 

28 

427406 

1591 

Mo. 

3404055 

228908 

11 

661959 

2339 

Mont. 

548889 

51251 

39 

127581 

2864 

Neb. 

1296372 

168083 

14 

438459 

2528 

Nev. 

77407 

6312 

48 

! 3349 

3854 

N. H. 

443083 

42556 

40 

95997 

3689 

N. J. 

3155900 

70491 

34 

130497 

3027 

N. M. 

360350 

12738 

45 

37805 

2210 

n. y . 

10385227 

756046 

2 

1481918 

4317 

N. C. 

2559123 

95748 

25 

290223 

2666 

N. D. 

646872 

138607 

17 

370707 

2657 

Ohio. 

5759394 

396318 

5 

888057 

3603 

Okla. 

2028283 

135821 

18 

456332 

2012 

Ore. 

783389 

92845 

27 

180462 

4136 

Pa. 

8720017 

421631 

4 

885855 

3990 

R. I. 

604397 

12099 

46 

21431 

4730 

S. C. 

1683724 

52955 

37 

187846 

2348 

S. D. 

636547 

124428 

20 

336892 

2339 

Tenn. 

2337885 

130286 

19 

415128 

2494 

Texas. 

4663228 

202974 

13 

833586 

1840 

Utah. 

449396 

29340 

42 

66724 

3466 

vt. 

352428 

122096 

21 

290122 

3560 

Va. 

2309187 

110942 

23 

357969 

2511 

Wash. 

1353621 

140525 

16 

238270 

4911 

W. Ya. 

1463701 

73690 

33 

181206 

2984 

Wis. 

2632067 

858259 

1 

1795122 

4016 

Wyo. 

U. S. 

194402 

105710620 

14614 

7805241 

43 

34997 

19675297 

2692 


i Pirtle. 





































































92 


LABORATORY MANUAL 


TABLE II 


Production of Manufactured Dairy Product? by States. 0) 
(.000 omitted.) 


State 

Dairy 

Butter 2 

Factory 

Butter 

Am. 

Cheese 

Swiss 

Cheese 

Brick 

Cheese 

All 

Other 

Cheese 

Sweet 

Cond. 

Milk 

Ala. 

28 ,490 

831 

51 



7 


Ariz. 

593 

602 

138 



5 


Ark. 

25 ,571 

996 






Cal. 

5,758 

81 ,948 

3,182 

518 


1 ,584 

13,065 

Col. 

5,776 

18,667 

1 ,120 


22 

162 

136 

Conn. 

1 ,926 

754 






Del. 

895 

154 

2 



2 

353 

Dist. Col. ... 

6 

10 




44 


Fla. 

1 ,162 

99 






Ga. 

30,257 

1 ,868 

3 





Ida. 

4,540 

9 ,883 

5 ,311 

1 

4 



Ill. 

25 ,064 

51 ,393 

3^275 

859 

585 

4,600 

33,859 

Ind. 

18,344 

51 ,541 

78 

12 

37 

224 

11 ,345 

Ia. 

25 ,423 

151 ,486 

361 


13 

346 

1 ,272 

Kan. 

17,456 

43,069 

no 



39 

1 ,620 

Ky. 

34,080 

12 ,244 




69 


La. 

4,252 

185 






Me. 

10,856 

402 




20 

968 

Md. 

6,163 

1 ,573 

18 



235 

1 ,019 

Mass. 

2,019 

1 ,844 




36 

86 

Mich. 

25,775 

64*820 

4,415 


415 

3,332 

42 ,954 

Minn. 

20 ,205 

200 ,340 

7 ,252 

19 

202 

615 

549 

Miss. 

20,759 

5,715 






Mo. 

29,471 

52,642 

224 



1 ,440 

164 

Mont. 

5 ,961 

10 ,667 

662 


85 

3 

Neb. 

13,761 

76,748 

69 


211 

44 

Nev. 

266 

2,361 





N. H. 

3,240 

424 




521 

82 

N. J. 

1 ,600 

438 

196 



1 ,583 

934 

N. M. 

1 ,404 

185 

135 



1 


N. Y. 

24 ,728 

19 ,264 

38 ,497 

1 ,590 

1 ,351 

22 ,264 

120,884 

N. C. 

25 ,552 

1 ,718 

111 



4 


N. D. 

14,413 

23,355 




4 


Ohio. 

30 ,264 

79,198 

128 

2,864 

92 

2,539 

21 ,856 

Okla. 

22,215 

14,065 






Ore. 

4,178 

18,128 

7,688 

4 

121 

29 

13 ,916 

Pa. 

38,469 

13,186 


411 


8,621 

25 430 

R. I. 

175 

76 




S. C. 

13,846 

537 






S. D. 

10,267 

27,447 

8 



5 


Tenn. 

37,166 

11 ,463 

284 





Teaxs. 

49 ,405 

10,956 




71 

160 

Utah. 

2,877 

7,500 

2,139 



47 

1 810 

Vt. 

3 ,877 

1 ,940 

1 ,506 



566 

15 234 

Va. 

25,477 

4,231 

257 




20 

Wash. 

5 ,900 

26 ,667 

2,762 


83 

1 ,846 

152 

W. Va. 

17 ,715 

276 




12 


Wis. 

8,666 

141 ,130 

227 ,937 

18,277 

30,240 

9 ,025 

37 ,985 

Wyo. 

1 ,423 

1 ,894 

1 ,791 



13 


U. S. 


1 ,256 ,920 

312 ,286 

24 ,555 

33 ,250 

60,133 

345 ,902 


1 Bureau of agricultural economics IJ. S. D. A., 1923. 

2 1920 census. 



























































































































DAIRY HUSBANDRY 


93 


Unsweet. 

Cond. 

Milk 

Filled 

Evap. 

Milk 

Pow¬ 

dered 

Milk 

Cond. 

Butter 

Milk 

Casein 

Malted 

Milk 

Milk 

Sugar 

Ice 

Cream 

State 








936 

Ala 

3,457 







213 

Ariz 








703 

A rk 

100,180 


10 ,788 

5 ,928 

4 ,754 


884 

8 865 

Cal 

22,018 


862 

292 


730 


1 ,584 

Col 





3 



3 ,032 

Eonu 

3 




134 



549 

Del 








1 061 

Dist Col 








765 

Fla 








1 ,258 

Ga 

13 ,668 




102 



271 

Ida 

75,641 

745 

2,083 

5 ,331 

146 

3,297 


13,233 

Ill. 

41 ,368 

1 ,217 

279 

2 ,852 

349 



5 ,832 

Ind. 

10,110 


1 ,060 

8 ,339 




5 ,087 

Ia 

15 ,034 


1 ,054 

3 ,559 



- 

2 ,448 

Kan. 

4 


3 

3 ,085 




1 ,461 

Ky. 

137 







1 ,105 

La. 





275 



1 ,025 

Me. 

13 ,652 


382 





3 ,590 

Md. 

159 




101 



7 ,522 

Mass. 

99 ,222 

4,117 

5,977 

2,945 

137 


243 

11 ’296 

Mich. 

2 ,464 


3 ,726 

305 

627 



3 ,310 

Minn. 

174 







567 

Miss. 



486 

1 ,885 




4 ,736 

Mo. 








491 

Mont. 

243 


4 ,566 

4 ,998 


2 


2 ,042 

Neb. 



285 





93 

Nev. 

28 




13 



385 

N. H. 

5 ,238 


415 


234 



7 ,004 

N. J. 








32 

N. M. 

203,190 


24,985 

340 

2,490 

128 

916 

20,527 

N. Y. 

141 







1 ,075 

N. C. 



713 

200 




520 

N. D. 

86 ,629 


380 

11 ,420 

501 

196 

430 

12,768 

Ohio 

713 



533 




1 ,672 

Okla. 

20 ,295 


82 

45 




1 ,363 

Ore. 

133 ,599 

110 

6 ,669 


616 



34,100 

Pa. 







1 ,365 

R. I. 








559 

S. C. 



493 

1 ,422 




706 

S. D. 








1 ,567 

Tenn. 

22 







3,665 

Texas 

23 ,734 







550 

Utah 

4 ,870 




936 


399 

282 

Vt. 

877 



109 

20 



1 ,759 

Va. 

90 122 

856 

9 ,564 

269 

11 



1 ,815 

Wash. 

21 





2,543 

W. Va. 

461 ,966 


7 ,319 

976 

3 ,063 

10 ,978 


5,892 

Wis. 







- 

188 

Wyo. 

1 ,428,979 

7,045 

82,171 

54 ,833 

14,548 

15,331 

2,872 

183,412 

U. S. 
































































































94 


LABORATORY MANUAL 


TABLE III. 

Utilization of Milk in the U. S. 1923 (Bureau of Agricultural Eco¬ 
nomics, U. S. D. A. 1923). 


Commodity 

Pounds Whole 
Milk Used 

000 Omitted 

Unit 

Require¬ 

ment 

Pounds 

Manufac¬ 

tured 

Produce 

000 Omitted 

Per cenl of 
T otal 
Milk 

Creamery Butter. 

26,296,494 

21 

1,252 ,214 

23.963 

Farm Butter. 

12,810,000 

21 

610 ,000 

11.673 

Cheese. 

3 ,989 ,470 

10 

1398 ,947 

3.636 

Condensed and Evap. Milk 

4,437,203 

2.5 

1 ,774 ,881 

4.044 

Powdered Milk. 

52 ,480 

8 

6 ,560 

.048 

Powdered Cream. 

6 ,232 

19 

328 

.006 

Malted Milk. 

33 ,728 

2.2 

15 ,331 

.031 


80 

1 

80 


Milk Chocolate 

149 ,500 



. 136 

Ice Cream (.Gals.). 

4,054,875 

13.75 

2 294 ,900 

3.695 

Total for Manufacturing .. 

51 ,830,062 



47.232 

Ytjlk - Household TTse 

50 ,440 ,000 


3 53 gal. 

45.965 

Fpd to Calves 

4,174 ,000 


4 200 lbs. 

3.803 







3,292 ,000 



3.000 






Grand Total. 

5109,736 ,062 



100.000 


! Includes 4,250,000 pounds of farm made cheese. 

2 Gallons. 

3 Per capita consumption. Population estimated at 110,663,501. 

4 Per calf. Calves estimated as 85 % of dairy cows. 

b Represents annual production of 24,552,000 cows, averaging 4,469.5 pounds of 
milk per cow. 


TABLE IV. 

Average Per Capita Consumption of Dairy Products Per Year. 


* 

Country 

Gallons 

Milk 

Pounds 

Butter 

Pounds 

Cheese 

Argentina . 


18 

3.7 

Australia . 


25.6 

4.8 

Canada. 

26.0 

27.7 

3.0 

Denmark. 

68.5 

19.0 

12.3 

Germany. 

61.0 

14.7 

9.5 

Netherlands. 

39.5 

16.8 

13.3 

Sweden . 

69.7 

16.5 


Switzerland. 

67.4 

7.5 

26.4 

United Kingdom. 

22.2 

17.0 

11.2 

United States.. 

43.0 

15.5 

4.2 






























































DAIRY HUSBANDRY 


95 


TABLE V. 

Production of Principal Dairy Products in Various Countries. (Pirtle and others.) 


Country 

Pounds 

Butter 

Pounds 

Cheese 

Pounds 

Condensed 

Argentina. 

56 ,722 ,973 

49 ,893 ,528 


Australia. 

165 ,468 ,791 

26,196,292 

63 ,289 ,645 

Canada. 

236 ,691 ,718 

149 ,201 ,856 

92,104 ,562 

Denmark. 

257 ,484 ,000 



Germany. 

529 ,104 ,000 



Netherlands. 

95 ,900,100 



Sweden. 

62 ,135 ,000 

17 ,603 ,731 


Switzerland. 

28 ,880,260 

63 *051*560 

55,115 ,000 

United Kingdom. 

282 ,056,320 

89 ,541 ,760 


United States. 

1,862,214 ,000 

398 ,947 ,000 

1 ,774,881 ,000 


TABLE VI. 

Population. Number of Dairy Cows, and Milk Production of Various Countries. 

(Pirtle and others.) 


Country 

Population 

Dairy Cows 

Yield 
per Cow, 
Lbs. 

Gals. Milk 
Produced 
000 omitted 2 

A rpcnt >n a 

8 ,279 ,159 

2 ,378 ,000 



Australia. 

6,067,430 

1 ,902,036 

2 ,719 

621,900 

Canada. 

8,134 ,000 

3,736,832 

3 ,779 

1 ,697 ,000 

Denmark.. 

2,940,979 

1 ,184 ,268 

5 ,666 

806 ,500 


41 ,475 ,523 

6,544 ,460 



Germany. 

55,086,000 

8 ,222 ,753 

4 ,350 

4 ,299 ,000 

Netherlands. 

6,778,699 

1 ,232 ,264 

7 ,585 

1 ,124 ,000 

Sweden . 

5 ,813 ,850 

1 ,607 ,060 

3 ,600 

695 ,300 

Switzerland. 

3 ,937 ,000 

>729 ,999 

6,950 

3609 ,800 

United Kingdom. 

46,000 ,000 

4,381 ,794 

5 ,934 

3,126,000 

United States. 

105,710,620 

19 ,675 ,297 

3 ,627 

8 ,576 ,000 


1 333,852 Goats additional. 

2 Calculated on basis of milk yield per cow. 

3 2,640 gallons Goat’s milk additional 




















































96 


LABORATORY MANUAL 


TABLE VII. 

Milk Solids and Water in Dairy Products. 
(Average of various authorities.) 


Product 

Fat 

Protein 

Sugar 

Ash 

Water 

Whole Milk . 

3.7 

3.2 

5.0 

.7 

87.4 

Skim Milk . 

.1 

3.1 

4.75 

.74 

91 .31 

Rutter Milk . 

.50 

3.0 

5.3 

.70 

90.5 

Whey . 

.36 

.84 

5.3 

.46 

93.04 

Cream 20 % . 

20.0 

3.0 

4.2 

.60 

72.20 

Cream 30 % . 

30.0 

2.7 

3.4 

.54 

63.36 


80.0 

1 .0 



16.0 


33.83 

23.72 


5.6 

36.84 

Condensed (Sweetened). 

11 .03 

10.14 

14.98 

2.12 

25.29 

Condensed (.Unsweetened). 

10.58 

9.75 

13.18 

2.07 

64 .05 

Condensed Skimmilk (Sweetened) 

.86 

10.96 

15.49 

2.38 

29.14 

Whole Milk Powder. 

28.20 

26.67 

47.88 

5.75 

1.50 

Skimmilk Powder . 

1.35 

37.70 

49.94 

8.21 

2.40 

Cream Powder (18%). 

70.47 

11.50 

15.01 

2.46 

.56 

Ruttermilk Powder. 

8.00 

34.00 

40.00 

9.50 

2.50 








TABLE VIII. 


Convenient Information 




9C 

To convert Centigrade to Fahrenheit 

F 

= 32 H- 

5 

To convert Fahrenheit to Centigrade 

C 

5 

= - (F — 32) 

Q 



& 

9R 

To convert Reaumur to Fahrenheit 

F 

= 32 H- 

4 

1 oz. Avoirdupois 

_ 

28.35 grams 

1 gram 

= 

.035 oz. Avoirdupois 

1 pound Avoirdupois 

= 

.4536 kilograms 

1 liquid quart 

= 

.9463 liter 

1 liter 

= 

1.0567 quarts 

1 gallon 

= 

3.7854 liters 

1 liter 

= 

.2642 gallons 

1 inch 

= 

2.54 centimeters 

1 centimeter 

= 

.3937 inch 

1 foot 

= 

.3048 meter 

1 meter 

= 

3.2808 feet 

1 gallon 

= 

231 cubic inches 

1 cubic foot 

= 

7.48 gallons 

1 cubic foot of water 

= 

62.5 pounds 

1 gallon of water 

= 

8.35 pounds 

Circumference of a circle 

= 

3.1416 X diameter 

Area of a circle 

= 

3.1416 X square of radius 






































DAIRY HUSBANDRY 


97 


l 


TABLE IX 


List of Popular Books and Magazines Relating to Dairy Manufacturing 


Books: 

Testing Milk and Its Products.Farrington & Woll 

Modern Methods of Testing Milk.Van Slyke 

A Manual of Milk Products. Stocking 

Principles of Dairying.Judkins 

Productive Dairying.Washburn 

Milk and its Products.Wing 

Farm Dairying...Larsen 

Market Milk.Kelley & Clement 

Principles and Practice of Buttermaking.McKay & Larsen 

The Book of Butter.Guthrie 

The Butter Industry.Hunziker 

Cheesemaking.Decker & Sammis 

The Book of Cheese.Thom Sc Fisk 

Manufacture of Ice Cream and Ices.Frandsen & Markham 

The Book of Ice Cream..'.Fisk 

Management of Dairy Plants.Mortensen 


Periodicals: 

Butter, Cheese and Egg Journal.:.Milwaukee, Wis. 

Chicago Dairy Produce.Chicago, Ill. 

Creamery & Milk Plant Monthly.Chicago, III. 

Creamery Journal.Waterloo, Iowa 

Dairy Record.St. Paul, Minn. 

Dairy World.Chicago, Ill. 

Hoard’s Dairyman.Port Atkinson, Wis. 

Ice Cream Trade Journal.New York, N. Y. 

Ice Cream Review.Milwaukee, Wis. 

Journal of Dairy Science.,.Baltimore, Md. 

Milk Dealer.....Milwaukee, Wis. 

New York Produce Review and American Creamery.New York, N. Y. 

Pacific Dairy Review.San Francisco, Cal. 

Western Milk Dealer and Dairyman.Seattle, Wash. 













































































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DEC 84 


N. MANCHESTER, 
INDIANA 46962 





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